Except for a few primitive organisms such as sponges (which have no nervous system) and cnidarians (which have a nervous system consisting of a diffuse nerve net), all living multicellular animals are bilaterians, meaning animals with a bilaterally symmetric body shape (that is, left and right sides that are approximate mirror images of each other). All bilaterians are thought to have descended from a common ancestor that appeared early in the Cambrian period, 485-540 million years ago, and it has been hypothesized that this common ancestor had the shape of a simple tubeworm with a segmented body. At a schematic level, that basic worm-shape continues to be reflected in the body and nervous system architecture of all modern bilaterians, including vertebrates. The fundamental bilateral body form is a tube with a hollow gut cavity running from the mouth to the anus, and a nerve cord with an enlargement (a ganglion) for each body segment, with an especially large ganglion at the front, called the brain. The brain is small and simple in some species, such as nematode worms; in other species, including vertebrates, it is the most complex organ in the body. Some types of worms, such as leeches, also have an enlarged ganglion at the back end of the nerve cord, known as a "tail brain".


There are a few types of existing bilaterians that lack a recognizable brain, including echinoderms, tunicates, and acoelomorphs (a group of primitive flatworms). It has not been definitively established whether the existence of these brainless species indicates that the earliest bilaterians lacked a brain, or whether their ancestors evolved in a way that led to the disappearance of a previously existing brain structure.


Two groups of invertebrates have notably complex brains: arthropods (insects, crustaceans, arachnids, and others), and cephalopods (octopuses, squids, and similar molluscs). The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the animal. Arthropods have a central brain with three divisions and large optical lobes behind each eye for visual processing. Cephalopods such as the octopus and squid have the largest brains of any invertebrates.


There are several invertebrate species whose brains have been studied intensively because they have properties that make them convenient for experimental work:


The first vertebrates appeared over 500 million years ago (Mya), during the Cambrian period, and may have resembled the modern hagfish in form. Sharks appeared about 450 Mya, amphibians about 400 Mya, reptiles about 350 Mya, and mammals about 200 Mya. Each species has an equally long evolutionary history, but the brains of modern hagfishes, lampreys, sharks, amphibians, reptiles, and mammals show a gradient of size and complexity that roughly follows the evolutionary sequence. All of these brains contain the same set of basic anatomical components, but many are rudimentary in the hagfish, whereas in mammals the foremost part (the telencephalon) is greatly elaborated and expanded.


Brains are most simply compared in terms of their size. The relationship between brain size, body size and other variables has been studied across a wide range of vertebrate species. As a rule, brain size increases with body size, but not in a simple linear proportion. In general, smaller animals tend to have larger brains, measured as a fraction of body size. For mammals, the relationship between brain volume and body mass essentially follows a power law with an exponent of about 0.75. This formula describes the central tendency, but every family of mammals departs from it to some degree, in a way that reflects in part the complexity of their behavior. For example, primates have brains 5 to 10 times larger than the formula predicts. Predators tend to have larger brains than their prey, relative to body size.


All vertebrate brains share a common underlying form, which appears most clearly during early stages of embryonic development. In its earliest form, the brain appears as three swellings at the front end of the neural tube; these swellings eventually become the forebrain, midbrain, and hindbrain (the prosencephalon, mesencephalon, and rhombencephalon, respectively). At the earliest stages of brain development, the three areas are roughly equal in size. In many classes of vertebrates, such as fish and amphibians, the three parts remain similar in size in the adult, but in mammals the forebrain becomes much larger than the other parts, and the midbrain becomes very small.


The brains of vertebrates are made of very soft tissue. Living brain tissue is pinkish on the outside and mostly white on the inside, with subtle variations in color. Vertebrate brains are surrounded by a system of connective tissue membranes called meninges that separate the skull from the brain. Blood vessels enter the central nervous system through holes in the meningeal layers. The cells in the blood vessel walls are joined tightly to one another, forming the blood–brain barrier, which blocks the passage of many toxins and pathogens (though at the same time blocking antibodies and some drugs, thereby presenting special challenges in treatment of diseases of the brain).


Neuroanatomists usually divide the vertebrate brain into six main regions: the telencephalon (cerebral hemispheres), diencephalon (thalamus and hypothalamus), mesencephalon (midbrain), cerebellum, pons, and medulla oblongata. Each of these areas has a complex internal structure. Some parts, such as the cerebral cortex and the cerebellar cortex, consist of layers that are folded or convoluted to fit within the available space. Other parts, such as the thalamus and hypothalamus, consist of clusters of many small nuclei. Thousands of distinguishable areas can be identified within the vertebrate brain based on fine distinctions of neural structure, chemistry, and connectivity.


Although the same basic components are present in all vertebrate brains, some branches of vertebrate evolution have led to substantial distortions of brain geometry, especially in the forebrain area. The brain of a shark shows the basic components in a straightforward way, but in teleost fishes (the great majority of existing fish species), the forebrain has become "everted", like a sock turned inside out. In birds, there are also major changes in forebrain structure. These distortions can make it difficult to match brain components from one species with those of another species.


The most obvious difference between the brains of mammals and other vertebrates is in terms of size. On average, a mammal has a brain roughly twice as large as that of a bird of the same body size, and ten times as large as that of a reptile of the same body size.


Size, however, is not the only difference: there are also substantial differences in shape. The hindbrain and midbrain of mammals are generally similar to those of other vertebrates, but dramatic differences appear in the forebrain, which is greatly enlarged and also altered in structure. The cerebral cortex is the part of the brain that most strongly distinguishes mammals. In non-mammalian vertebrates, the surface of the cerebrum is lined with a comparatively simple three-layered structure called the pallium. In mammals, the pallium evolves into a complex six-layered structure called neocortex or isocortex. Several areas at the edge of the neocortex, including the hippocampus and amygdala, are also much more extensively developed in mammals than in other vertebrates.


The elaboration of the cerebral cortex carries with it changes to other brain areas. The superior colliculus, which plays a major role in visual control of behavior in most vertebrates, shrinks to a small size in mammals, and many of its functions are taken over by visual areas of the cerebral cortex. The cerebellum of mammals contains a large portion (the neocerebellum) dedicated to supporting the cerebral cortex, which has no counterpart in other vertebrates.


The brains of humans and other primates contain the same structures as the brains of other mammals, but are generally larger in proportion to body size. The most widely accepted way of comparing brain sizes across species is the so-called encephalization quotient (EQ), which takes into account the nonlinearity of the brain-to-body relationship. Humans have an average EQ in the 7-to-8 range, while most other primates have an EQ in the 2-to-3 range. Dolphins have values higher than those of primates other than humans, but nearly all other mammals have EQ values that are substantially lower.


Most of the enlargement of the primate brain comes from a massive expansion of the cerebral cortex, especially the prefrontal cortex and the parts of the cortex involved in vision. The visual processing network of primates includes at least 30 distinguishable brain areas, with a complex web of interconnections. It has been estimated that visual processing areas occupy more than half of the total surface of the primate neocortex. The prefrontal cortex carries out functions that include planning, working memory, motivation, attention, and executive control. It takes up a much larger proportion of the brain for primates than for other species, and an especially large fraction of the human brain.


For vertebrates, the early stages of neural development are similar across all species. As the embryo transforms from a round blob of cells into a wormlike structure, a narrow strip of ectoderm running along the midline of the back is induced to become the neural plate, the precursor of the nervous system. The neural plate folds inward to form the neural groove, and then the lips that line the groove merge to enclose the neural tube, a hollow cord of cells with a fluid-filled ventricle at the center. At the front end, the ventricles and cord swell to form three vesicles that are the precursors of the forebrain, midbrain, and hindbrain. At the next stage, the forebrain splits into two vesicles called the telencephalon (which will contain the cerebral cortex, basal ganglia, and related structures) and the diencephalon (which will contain the thalamus and hypothalamus). At about the same time, the hindbrain splits into the metencephalon (which will contain the cerebellum and pons) and the myelencephalon (which will contain the medulla oblongata). Each of these areas contains proliferative zones where neurons and glial cells are generated; the resulting cells then migrate, sometimes for long distances, to their final positions.


Once a neuron is in place, it extends dendrites and an axon into the area around it. Axons, because they commonly extend a great distance from the cell body and need to reach specific targets, grow in a particularly complex way. The tip of a growing axon consists of a blob of protoplasm called a growth cone, studded with chemical receptors. These receptors sense the local environment, causing the growth cone to be attracted or repelled by various cellular elements, and thus to be pulled in a particular direction at each point along its path. The result of this pathfinding process is that the growth cone navigates through the brain until it reaches its destination area, where other chemical cues cause it to begin generating synapses. Considering the entire brain, thousands of genes create products that influence axonal pathfinding.


In humans and many other mammals, new neurons are created mainly before birth, and the infant brain contains substantially more neurons than the adult brain. There are, however, a few areas where new neurons continue to be generated throughout life. The two areas for which adult neurogenesis is well established are the olfactory bulb, which is involved in the sense of smell, and the dentate gyrus of the hippocampus, where there is evidence that the new neurons play a role in storing newly acquired memories. With these exceptions, however, the set of neurons that is present in early childhood is the set that is present for life. Glial cells are different: as with most types of cells in the body, they are generated throughout the lifespan.


The functions of the brain depend on the ability of neurons to transmit electrochemical signals to other cells, and their ability to respond appropriately to electrochemical signals received from other cells. The electrical properties of neurons are controlled by a wide variety of biochemical and metabolic processes, most notably the interactions between neurotransmitters and receptors that take place at synapses.


Neurotransmitters are chemicals that are released at synapses when an action potential activates them—neurotransmitters attach themselves to receptor molecules on the membrane of the synapse's target cell, and thereby alter the electrical or chemical properties of the receptor molecules. With few exceptions, each neuron in the brain releases the same chemical neurotransmitter, or combination of neurotransmitters, at all the synaptic connections it makes with other neurons; this rule is known as Dale's principle. Thus, a neuron can be characterized by the neurotransmitters that it releases. The great majority of psychoactive drugs exert their effects by altering specific neurotransmitter systems. This applies to drugs such as cannabinoids, nicotine, heroin, cocaine, alcohol, fluoxetine, chlorpromazine, and many others.


The two neurotransmitters that are used most widely in the vertebrate brain are glutamate, which almost always exerts excitatory effects on target neurons, and gamma-aminobutyric acid (GABA), which is almost always inhibitory. Neurons using these transmitters can be found in nearly every part of the brain. Because of their ubiquity, drugs that act on glutamate or GABA tend to have broad and powerful effects. Some general anesthetics act by reducing the effects of glutamate; most tranquilizers exert their sedative effects by enhancing the effects of GABA.


There are dozens of other chemical neurotransmitters that are used in more limited areas of the brain, often areas dedicated to a particular function. Serotonin, for example—the primary target of antidepressant drugs and many dietary aids—comes exclusively from a small brainstem area called the Raphe nuclei. Norepinephrine, which is involved in arousal, comes exclusively from a nearby small area called the locus coeruleus. Other neurotransmitters such as acetylcholine and dopamine have multiple sources in the brain, but are not as ubiquitously distributed as glutamate and GABA.


As a side effect of the electrochemical processes used by neurons for signaling, brain tissue generates electric fields when it is active. When large numbers of neurons show synchronized activity, the electric fields that they generate can be large enough to detect outside the skull, using electroencephalography (EEG) or magnetoencephalography (MEG). EEG recordings, along with recordings made from electrodes implanted inside the brains of animals such as rats, show that the brain of a living animal is constantly active, even during sleep. Each part of the brain shows a mixture of rhythmic and nonrhythmic activity, which may vary according to behavioral state. In mammals, the cerebral cortex tends to show large slow delta waves during sleep, faster alpha waves when the animal is awake but inattentive, and chaotic-looking irregular activity when the animal is actively engaged in a task. During an epileptic seizure, the brain's inhibitory control mechanisms fail to function and electrical activity rises to pathological levels, producing EEG traces that show large wave and spike patterns not seen in a healthy brain. Relating these population-level patterns to the computational functions of individual neurons is a major focus of current research in neurophysiology.


All vertebrates have a blood–brain barrier that allows metabolism inside the brain to operate differently from metabolism in other parts of the body. Glial cells play a major role in brain metabolism by controlling the chemical composition of the fluid that surrounds neurons, including levels of ions and nutrients.


Brain tissue consumes a large amount of energy in proportion to its volume, so large brains place severe metabolic demands on animals. The need to limit body weight in order, for example, to fly, has apparently led to selection for a reduction of brain size in some species, such as bats. Most of the brain's energy consumption goes into sustaining the electric charge (membrane potential) of neurons. Most vertebrate species devote between 2% and 8% of basal metabolism to the brain. In primates, however, the percentage is much higher—in humans it rises to 20–25%. The energy consumption of the brain does not vary greatly over time, but active regions of the cerebral cortex consume somewhat more energy than inactive regions; this forms the basis for the functional brain imaging methods PET, fMRI, and NIRS. The brain typically gets most of its energy from oxygen-dependent metabolism of glucose (i.e., blood sugar), but ketones provide a major alternative source, together with contributions from medium chain fatty acids (caprylic and heptanoic acids), lactate, acetate, and possibly amino acids.


From an evolutionary-biological perspective, the function of the brain is to provide coherent control over the actions of an animal. A centralized brain allows groups of muscles to be co-activated in complex patterns; it also allows stimuli impinging on one part of the body to evoke responses in other parts, and it can prevent different parts of the body from acting at cross-purposes to each other.


The invention of electronic computers in the 1940s, along with the development of mathematical information theory, led to a realization that brains can potentially be understood as information processing systems. This concept formed the basis of the field of cybernetics, and eventually gave rise to the field now known as computational neuroscience. The earliest attempts at cybernetics were somewhat crude in that they treated the brain as essentially a digital computer in disguise, as for example in John von Neumann's 1958 book, The Computer and the Brain. Over the years, though, accumulating information about the electrical responses of brain cells recorded from behaving animals has steadily moved theoretical concepts in the direction of increasing realism.


The essence of the information processing approach is to try to understand brain function in terms of information flow and implementation of algorithms. One of the most influential early contributions was a 1959 paper titled What the frog's eye tells the frog's brain: the paper examined the visual responses of neurons in the retina and optic tectum of frogs, and came to the conclusion that some neurons in the tectum of the frog are wired to combine elementary responses in a way that makes them function as "bug perceivers". A few years later David Hubel and Torsten Wiesel discovered cells in the primary visual cortex of monkeys that become active when sharp edges move across specific points in the field of view—a discovery for which they won a Nobel Prize. Follow-up studies in higher-order visual areas found cells that detect binocular disparity, color, movement, and aspects of shape, with areas located at increasing distances from the primary visual cortex showing increasingly complex responses. Other investigations of brain areas unrelated to vision have revealed cells with a wide variety of response correlates, some related to memory, some to abstract types of cognition such as space.


Furthermore, even single neurons appear to be complex and capable of performing computations. So, brain models that don't reflect this are arguably too abstractive to be representative of brain operation; models that do try to capture this are very computationally expensive and arguably intractable with present computational resources. However, having said this, the Human Brain Project is trying to build a realistic, detailed computational model of the entire human brain. It remains to be seen what level of success they can achieve in the time frame of the project and the wisdom of it has been publicly contested, with high-profile scientists on both sides of the argument.


One of the primary functions of a brain is to extract biologically relevant information from sensory inputs. The human brain is provided with information about light, sound, the chemical composition of the atmosphere, temperature, head orientation, limb position, the chemical composition of the bloodstream, and more. In other animals additional senses may be present, such as the infrared heat-sense of snakes, the magnetic field sense of some birds, or the electric field sense of some types of fish. Moreover, other animals may develop existing sensory systems in new ways, such as the adaptation by bats of the auditory sense into a form of sonar. One way or another, all of these sensory modalities are initially detected by specialized sensors that project signals into the brain.


Each sensory system begins with specialized receptor cells, such as light-receptive neurons in the retina of the eye, vibration-sensitive neurons in the cochlea of the ear, or pressure-sensitive neurons in the skin. The axons of sensory receptor cells travel into the spinal cord or brain, where they transmit their signals to a first-order sensory nucleus dedicated to one specific sensory modality. This primary sensory nucleus sends information to higher-order sensory areas that are dedicated to the same modality. Eventually, via a way-station in the thalamus, the signals are sent to the cerebral cortex, where they are processed to extract biologically relevant features, and integrated with signals coming from other sensory systems.


Motor systems are areas of the brain that are directly or indirectly involved in producing body movements, that is, in activating muscles. Except for the muscles that control the eye, which are driven by nuclei in the midbrain, all the voluntary muscles in the body are directly innervated by motor neurons in the spinal cord and hindbrain. Spinal motor neurons are controlled both by neural circuits intrinsic to the spinal cord, and by inputs that descend from the brain. The intrinsic spinal circuits implement many reflex responses, and contain pattern generators for rhythmic movements such as walking or swimming. The descending connections from the brain allow for more sophisticated control.


The brain contains several motor areas that project directly to the spinal cord. At the lowest level are motor areas in the medulla and pons, which control stereotyped movements such as walking, breathing, or swallowing. At a higher level are areas in the midbrain, such as the red nucleus, which is responsible for coordinating movements of the arms and legs. At a higher level yet is the primary motor cortex, a strip of tissue located at the posterior edge of the frontal lobe. The primary motor cortex sends projections to the subcortical motor areas, but also sends a massive projection directly to the spinal cord, through the pyramidal tract. This direct corticospinal projection allows for precise voluntary control of the fine details of movements. Other motor-related brain areas exert secondary effects by projecting to the primary motor areas. Among the most important secondary areas are the premotor cortex, basal ganglia, and cerebellum.


In addition to all of the above, the brain and spinal cord contain extensive circuitry to control the autonomic nervous system, which works by secreting hormones and by modulating the "smooth" muscles of the gut. The autonomic nervous system affects heart rate, digestion, respiration rate, salivation, perspiration, urination, and sexual arousal, and several other processes. Most of its functions are not under direct voluntary control.


A key component of the arousal system is the suprachiasmatic nucleus (SCN), a tiny part of the hypothalamus located directly above the point at which the optic nerves from the two eyes cross. The SCN contains the body's central biological clock. Neurons there show activity levels that rise and fall with a period of about 24 hours, circadian rhythms: these activity fluctuations are driven by rhythmic changes in expression of a set of "clock genes". The SCN continues to keep time even if it is excised from the brain and placed in a dish of warm nutrient solution, but it ordinarily receives input from the optic nerves, through the retinohypothalamic tract (RHT), that allows daily light-dark cycles to calibrate the clock.


The SCN projects to a set of areas in the hypothalamus, brainstem, and midbrain that are involved in implementing sleep-wake cycles. An important component of the system is the reticular formation, a group of neuron-clusters scattered diffusely through the core of the lower brain. Reticular neurons send signals to the thalamus, which in turn sends activity-level-controlling signals to every part of the cortex. Damage to the reticular formation can produce a permanent state of coma.


Sleep involves great changes in brain activity. Until the 1950s it was generally believed that the brain essentially shuts off during sleep, but this is now known to be far from true; activity continues, but patterns become very different. There are two types of sleep: REM sleep (with dreaming) and NREM (non-REM, usually without dreaming) sleep, which repeat in slightly varying patterns throughout a sleep episode. Three broad types of distinct brain activity patterns can be measured: REM, light NREM and deep NREM. During deep NREM sleep, also called slow wave sleep, activity in the cortex takes the form of large synchronized waves, whereas in the waking state it is noisy and desynchronized. Levels of the neurotransmitters norepinephrine and serotonin drop during slow wave sleep, and fall almost to zero during REM sleep; levels of acetylcholine show the reverse pattern.


For any animal, survival requires maintaining a variety of parameters of bodily state within a limited range of variation: these include temperature, water content, salt concentration in the bloodstream, blood glucose levels, blood oxygen level, and others. The ability of an animal to regulate the internal environment of its body—the milieu intérieur, as pioneering physiologist Claude Bernard called it—is known as homeostasis (Greek for "standing still"). Maintaining homeostasis is a crucial function of the brain. The basic principle that underlies homeostasis is negative feedback: any time a parameter diverges from its set-point, sensors generate an error signal that evokes a response that causes the parameter to shift back toward its optimum value. (This principle is widely used in engineering, for example in the control of temperature using a thermostat.)


In vertebrates, the part of the brain that plays the greatest role is the hypothalamus, a small region at the base of the forebrain whose size does not reflect its complexity or the importance of its function. The hypothalamus is a collection of small nuclei, most of which are involved in basic biological functions. Some of these functions relate to arousal or to social interactions such as sexuality, aggression, or maternal behaviors; but many of them relate to homeostasis. Several hypothalamic nuclei receive input from sensors located in the lining of blood vessels, conveying information about temperature, sodium level, glucose level, blood oxygen level, and other parameters. These hypothalamic nuclei send output signals to motor areas that can generate actions to rectify deficiencies. Some of the outputs also go to the pituitary gland, a tiny gland attached to the brain directly underneath the hypothalamus. The pituitary gland secretes hormones into the bloodstream, where they circulate throughout the body and induce changes in cellular activity.


Most organisms studied to date utilize a reward–punishment mechanism: for instance, worms and insects can alter their behavior to seek food sources or to avoid dangers. In vertebrates, the reward-punishment system is implemented by a specific set of brain structures, at the heart of which lie the basal ganglia, a set of interconnected areas at the base of the forebrain. There is substantial evidence that the basal ganglia are the central site at which decisions are made: the basal ganglia exert a sustained inhibitory control over most of the motor systems in the brain; when this inhibition is released, a motor system is permitted to execute the action it is programmed to carry out. Rewards and punishments function by altering the relationship between the inputs that the basal ganglia receive and the decision-signals that are emitted. The reward mechanism is better understood than the punishment mechanism, because its role in drug abuse has caused it to be studied very intensively. Research has shown that the neurotransmitter dopamine plays a central role: addictive drugs such as cocaine, amphetamine, and nicotine either cause dopamine levels to rise or cause the effects of dopamine inside the brain to be enhanced.


Almost all animals are capable of modifying their behavior as a result of experience—even the most primitive types of worms. Because behavior is driven by brain activity, changes in behavior must somehow correspond to changes inside the brain. Theorists dating back to Santiago Ramón y Cajal argued that the most plausible explanation is that learning and memory are expressed as changes in the synaptic connections between neurons. Until 1970, however, experimental evidence to support the synaptic plasticity hypothesis was lacking. In 1971 Tim Bliss and Terje Lømo published a paper on a phenomenon now called long-term potentiation: the paper showed clear evidence of activity-induced synaptic changes that lasted for at least several days. Since then technical advances have made these sorts of experiments much easier to carry out, and thousands of studies have been made that have clarified the mechanism of synaptic change, and uncovered other types of activity-driven synaptic change in a variety of brain areas, including the cerebral cortex, hippocampus, basal ganglia, and cerebellum. Brain-derived neurotrophic factor (BDNF) and physical activity appear to play a beneficial role in the process.


The field of neuroscience encompasses all approaches that seek to understand the brain and the rest of the nervous system. Psychology seeks to understand mind and behavior, and neurology is the medical discipline that diagnoses and treats diseases of the nervous system. The brain is also the most important organ studied in psychiatry, the branch of medicine that works to study, prevent, and treat mental disorders. Cognitive science seeks to unify neuroscience and psychology with other fields that concern themselves with the brain, such as computer science (artificial intelligence and similar fields) and philosophy.


The oldest method of studying the brain is anatomical, and until the middle of the 20th century, much of the progress in neuroscience came from the development of better cell stains and better microscopes. Neuroanatomists study the large-scale structure of the brain as well as the microscopic structure of neurons and their components, especially synapses. Among other tools, they employ a plethora of stains that reveal neural structure, chemistry, and connectivity. In recent years, the development of immunostaining techniques has allowed investigation of neurons that express specific sets of genes. Also, functional neuroanatomy uses medical imaging techniques to correlate variations in human brain structure with differences in cognition or behavior.


Neurophysiologists study the chemical, pharmacological, and electrical properties of the brain: their primary tools are drugs and recording devices. Thousands of experimentally developed drugs affect the nervous system, some in highly specific ways. Recordings of brain activity can be made using electrodes, either glued to the scalp as in EEG studies, or implanted inside the brains of animals for extracellular recordings, which can detect action potentials generated by individual neurons. Because the brain does not contain pain receptors, it is possible using these techniques to record brain activity from animals that are awake and behaving without causing distress. The same techniques have occasionally been used to study brain activity in human patients suffering from intractable epilepsy, in cases where there was a medical necessity to implant electrodes to localize the brain area responsible for epileptic seizures. Functional imaging techniques such as functional magnetic resonance imaging are also used to study brain activity; these techniques have mainly been used with human subjects, because they require a conscious subject to remain motionless for long periods of time, but they have the great advantage of being noninvasive.


Another approach to brain function is to examine the consequences of damage to specific brain areas. Even though it is protected by the skull and meninges, surrounded by cerebrospinal fluid, and isolated from the bloodstream by the blood–brain barrier, the delicate nature of the brain makes it vulnerable to numerous diseases and several types of damage. In humans, the effects of strokes and other types of brain damage have been a key source of information about brain function. Because there is no ability to experimentally control the nature of the damage, however, this information is often difficult to interpret. In animal studies, most commonly involving rats, it is possible to use electrodes or locally injected chemicals to produce precise patterns of damage and then examine the consequences for behavior.


Computational neuroscience encompasses two approaches: first, the use of computers to study the brain; second, the study of how brains perform computation. On one hand, it is possible to write a computer program to simulate the operation of a group of neurons by making use of systems of equations that describe their electrochemical activity; such simulations are known as biologically realistic neural networks. On the other hand, it is possible to study algorithms for neural computation by simulating, or mathematically analyzing, the operations of simplified "units" that have some of the properties of neurons but abstract out much of their biological complexity. The computational functions of the brain are studied both by computer scientists and neuroscientists.


Recent years have seen increasing applications of genetic and genomic techniques to the study of the brain  and a focus on the roles of neurotrophic factors and physical activity in neuroplasticity. The most common subjects are mice, because of the availability of technical tools. It is now possible with relative ease to "knock out" or mutate a wide variety of genes, and then examine the effects on brain function. More sophisticated approaches are also being used: for example, using Cre-Lox recombination it is possible to activate or deactivate genes in specific parts of the brain, at specific times.


The oldest brain to have been discovered was in Armenia in the Areni-1 cave complex. The brain, estimated to be over 5,000 years old, was found in the skull of a 12 to 14-year-old girl. Although the brains were shriveled, they were well preserved due to the climate found inside the cave.


Early philosophers were divided as to whether the seat of the soul lies in the brain or heart. Aristotle favored the heart, and thought that the function of the brain was merely to cool the blood. Democritus, the inventor of the atomic theory of matter, argued for a three-part soul, with intellect in the head, emotion in the heart, and lust near the liver. Hippocrates, the "father of medicine", came down unequivocally in favor of the brain. In his treatise on epilepsy he wrote:


The Roman physician Galen also argued for the importance of the brain, and theorized in some depth about how it might work. Galen traced out the anatomical relationships among brain, nerves, and muscles, demonstrating that all muscles in the body are connected to the brain through a branching network of nerves. He postulated that nerves activate muscles mechanically by carrying a mysterious substance he called pneumata psychikon, usually translated as "animal spirits". Galen's ideas were widely known during the Middle Ages, but not much further progress came until the Renaissance, when detailed anatomical study resumed, combined with the theoretical speculations of René Descartes and those who followed him. Descartes, like Galen, thought of the nervous system in hydraulic terms. He believed that the highest cognitive functions are carried out by a non-physical res cogitans, but that the majority of behaviors of humans, and all behaviors of animals, could be explained mechanistically.


The first real progress toward a modern understanding of nervous function, though, came from the investigations of Luigi Galvani, who discovered that a shock of static electricity applied to an exposed nerve of a dead frog could cause its leg to contract. Since that time, each major advance in understanding has followed more or less directly from the development of a new technique of investigation. Until the early years of the 20th century, the most important advances were derived from new methods for staining cells. Particularly critical was the invention of the Golgi stain, which (when correctly used) stains only a small fraction of neurons, but stains them in their entirety, including cell body, dendrites, and axon. Without such a stain, brain tissue under a microscope appears as an impenetrable tangle of protoplasmic fibers, in which it is impossible to determine any structure. In the hands of Camillo Golgi, and especially of the Spanish neuroanatomist Santiago Ramón y Cajal, the new stain revealed hundreds of distinct types of neurons, each with its own unique dendritic structure and pattern of connectivity.


In the first half of the 20th century, advances in electronics enabled investigation of the electrical properties of nerve cells, culminating in work by Alan Hodgkin, Andrew Huxley, and others on the biophysics of the action potential, and the work of Bernard Katz and others on the electrochemistry of the synapse. These studies complemented the anatomical picture with a conception of the brain as a dynamic entity. Reflecting the new understanding, in 1942 Charles Sherrington visualized the workings of the brain waking from sleep:


In the second half of the 20th century, developments in chemistry, electron microscopy, genetics, computer science, functional brain imaging, and other fields progressively opened new windows into brain structure and function. In the United States, the 1990s were officially designated as the "Decade of the Brain" to commemorate advances made in brain research, and to promote funding for such research.


In the 21st century, these trends have continued, and several new approaches have come into prominence, including multielectrode recording, which allows the activity of many brain cells to be recorded all at the same time; genetic engineering, which allows molecular components of the brain to be altered experimentally; genomics, which allows variations in brain structure to be correlated with variations in DNA properties and neuroimaging.


Near East (French: Proche-Orient) is a geographical term that roughly encompasses Western Asia. Despite having varying definitions within different academic circles, the term was originally applied to the maximum extent of the Ottoman Empire. The term has fallen into disuse in English, and has been replaced by the term Middle East.


The Encyclopædia Britannica defines the Near East as including Armenia, Azerbaijan, Bahrain, Cyprus, Egypt, Georgia, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, Libya, Oman, Palestine, Qatar, Saudi Arabia, Sudan, Syria, Turkey, the United Arab Emirates, the West Bank, and Yemen. The Food and Agriculture Organization (FAO) of the United Nations defines the region similarly, but also includes Afghanistan while excluding the countries of North Africa and the Palestinian territories. According to the National Geographic Society, the terms Near East and Middle East denote the same territories and are 'generally accepted as comprising the countries of the Arabian Peninsula, Cyprus, Egypt, Iraq, Iran, Israel, Jordan, Lebanon, Palestinian territories, Syria, and Turkey'.


At the beginning of the 19th century the Ottoman Empire included all of the Balkan Peninsula north to the southern edge of the Hungarian Plain, but by 1914 had lost all of it except Constantinople and Eastern Thrace to the rise of Balkan nationalism, which saw the independence of Greece, Serbia, the Danubian Principalities and Bulgaria. Up until 1912 the Ottomans retained a band of territory including Albania, Macedonia and Thrace, which were lost in the two Balkan Wars of 1912–13.


The Ottoman Empire, believed to be about to collapse, was portrayed in the press as the sick man of Europe". The Balkan states, with the partial exception of Bosnia and Albania, were primarily Christian. Starting in 1894 the Ottomans struck at the Armenians on the explicit grounds that they were a non-Muslim people and as such were a potential threat to the Muslim empire within which they resided. The Hamidian Massacres aroused the indignation of the entire Christian world. In the United States the now aging Julia Ward Howe, author of the Battle Hymn of the Republic, leaped into the war of words and joined the Red Cross. Relations of minorities within the Ottoman Empire and the disposition of former Ottoman lands became known as the "Eastern Question," as the Ottomans were on the east of Europe.


It now became relevant to define the east of the eastern question. In about the middle of the 19th century "Near East" came into use to describe that part of the east closest to Europe. The term "Far East" appeared contemporaneously meaning Japan, China, Korea, Indonesia and Viet Nam; in short, the East Indies. "Near East" applied to what had been mainly known as the Levant, which was in the jurisdiction of the Ottoman Porte, or government. Those who used the term had little choice about its meaning. They could not set foot on most of the shores of the southern and central Mediterranean from the Gulf of Sidra to Albania without permits from the Ottoman Empire.


Some regions beyond the Ottoman Porte were included. One was North Africa west of Egypt. It was occupied by piratical kingdoms of the Barbary Coast, de facto independent since the 18th century. Formerly part of the empire at its apogee. Iran was included because it could not easily be reached except through the Ottoman Empire or neighboring Russia. In the 1890s the term tended to focus on the conflicts in the Balkan states and Armenia. The demise of the sick man of Europe left considerable confusion as to what was to be meant by "Near East". It is now generally used only in historical contexts, to describe the countries of Western Asia from the Mediterranean to (or including) Iran. There is, in short, no universally understood fixed inventory of nations, languages or historical assets defined to be in it.


The geographical terms "Near East" and "Far East" referring to areas of the globe in or contiguous to the former British Empire and the neighboring colonies of the Dutch, Portuguese, Spanish and Germans, fit together as a pair based on the opposites of far and near, suggesting that they were innovated together. They appear together in the journals of the mid-19th century. Both terms were used before then with local British and American meanings: the near or far east of a field, village or shire.


There was a linguistic predisposition to use such terms. The Romans had used them in near Gaul / far Gaul, near Spain / far Spain and others. Before them the Greeks had the habit, which appears in Linear B, the oldest known script of Europe, referring to the near province and the far province of the kingdom of Pylos. Usually these terms were given with reference to a geographic feature, such as a mountain range or a river.


Ptolemy's Geography divided Asia on a similar basis. In the north is "Scythia this side of the Himalayas" and "Scythia beyond the Himalayas." To the south is "India on this side of the Ganges" and "India beyond the Ganges." Asia began on the coast of Anatolia ("land of the rising sun"). Beyond the Ganges and Himalayas (including the Tien Shan) were Serica and Serae (sections of China) and some other identifiable far eastern locations known to the voyagers and geographers but not to the general European public.


By the time of John Seller's Atlas Maritima of 1670, "India Beyond the Ganges" had become "the East Indies" including China, Korea, southeast Asia and the islands of the Pacific in a map that was every bit as distorted as Ptolemy's, despite the lapse of approximately 1500 years. That "east" in turn was only an English translation of Latin Oriens and Orientalis, "the land of the rising sun," used since Roman times for "east." The world map of Jodocus Hondius of 1590 labels all of Asia from the Caspian to the Pacific as India Orientalis, shortly to appear in translation as the East Indies.


Elizabeth I of England, primarily interested in trade with the east, collaborated with English merchants to form the first trading companies to the far-flung regions, using their own jargon. Their goals were to obtain trading concessions by treaty. The queen chartered the Company of Merchants of the Levant, shortened to Levant Company, and soon known also as The Turkey Company, in 1581. In 1582, the ship The Great Susan transported the first ambassador, William Harebone, to the Ottoman Porte (government of the Ottoman Empire) at Constantinople. Compared to Anatolia, Levant also means "land of the rising sun," but where Anatolia always only meant the projection of land currently occupied by the Republic of Turkey, Levant meant anywhere in the domain ruled by the Ottoman Porte. The East India Company (short for a much longer formal name) was chartered in 1600 for trade to the East Indies.


It has pleased western historians to write of a decline of the Ottoman Empire as though a stable and uncontested polity of that name once existed. The borders did expand and contract but they were always dynamic and always in "question" right from the beginning. The Ottoman Empire was created from the lands of the former eastern Roman Empire on the occasion of the latter's violent demise. The last Roman emperor died fighting hand-to-hand in the streets of his capital, Constantinople, overwhelmed by the Ottoman military, in May, 1453. The victors inherited his remaining territory in the Balkans.


The populations of those lands did not accept Turkish rule. The Turks to them were foreigners with completely different customs, way of life, and language. Intervals when there was no unrest were rare. The Hungarians had thrown off Turkish rule by 1688. Serbia was created by the Serbian Revolution, 1815–1833. The Greek War of Independence, 1821–1832, created modern Greece, which recovered most of the lands of ancient Greece, but could not gain Constantinople. The Ottoman Porte was continuously under attack from some quarter in its empire, primarily the Balkans. Also, on a number of occasions in the early 19th century, American and British warships had to attack the Barbary pirates to stop their piracy and recover thousands of enslaved Europeans and Americans.


In 1853 the Russian Empire on behalf of the Slavic Balkan states began to question the very existence of the Ottoman Empire. The result was the Crimean War, 1853–1856, in which the British Empire and the French Empire supported the Ottoman Empire in its struggle against the incursions of the Russian Empire. Eventually, the Ottoman Empire lost control of the Balkan region.


Until about 1855 the words near east and far east did not refer to any particular region. The far East, a phrase containing a noun, East, qualified by an adjective, far, could be at any location in the "far east" of the speaker's home territory. The Ottoman Empire, for example, was the far East as much as the East Indies. The Crimean War brought a change in vocabulary with the introduction of terms more familiar to the late 19th century. The Russian Empire had entered a more aggressive phase, becoming militarily active against the Ottoman Empire and also against China, with territorial aggrandizement explicitly in mind. Rethinking its policy the British government decided that the two polities under attack were necessary for the balance of power. It therefore undertook to oppose the Russians in both places, one result being the Crimean War. During that war the administration of the British Empire began promulgating a new vocabulary, giving specific regional meaning to "the Near East," the Ottoman Empire, and "the Far East," the East Indies. The two terms were now compound nouns often shown hyphenated.


In 1855 a reprint of a letter earlier sent to The Times appeared in Littel's Living Age. Its author, an "official Chinese interpreter of 10 years' active service" and a member of the Oriental Club, Thomas Taylor Meadows, was replying to the suggestion by another interpreter that the British Empire was wasting its resources on a false threat from Russia against China. Toward the end of the letter he said:


Much of the colonial administration belonged to this club, which had been formed by the Duke of Wellington. Meadows' terminology must represent usage by that administration. If not the first use of the terms, the letter to the Times was certainly one of the earliest presentations of this vocabulary to the general public. They became immediately popular, supplanting "Levant" and "East Indies," which gradually receded to minor usages and then began to change meaning.


"Near East" remained popular in diplomatic, trade and journalistic circles, but a variation soon developed among the scholars and the men of the cloth and their associates: "the Nearer East," reverting to the classical and then more scholarly distinction of "nearer" and "farther." They undoubtedly saw a need to separate the Biblical lands from the terrain of the Ottoman Empire. The Christians saw the country as the land of the Old and New Testaments, where Christianity had developed. The scholars in the field of studies that eventually became Biblical archaeology attempted to define it on the basis of archaeology.


For example, The London Review of 1861 (Telford and Barber, unsigned) in reviewing several works by Rawlinson, Layard and others, defined themselves as making:


The regions in their inventory were Assyria, Chaldea, Mesopotamia, Persia, Armenia, Egypt, Arabia, Syria, Palestine, Ethiopia, Caucasus, Libya, Anatolia and Abyssinia. Explicitly excluded is India. No mention is made of the Balkans.


Hogarth then proceeds to say where and why in some detail, but no more mention is made of the classics. His analysis is geopolitical. His map delineates the Nearer East with regular lines as though surveyed. They include Iran, the Balkans, but not the Danube lands, Egypt, but not the rest of North Africa. Except for the Balkans, the region matches the later Middle East. It differs from the Ottoman Empire of the times in including Greece and Iran. Hogarth gives no evidence of being familiar with the contemporaneous initial concept of the Middle East.


In the last years of the 19th century the term "Near East" acquired considerable disrepute in eyes of the English-speaking public as did the Ottoman Empire itself. The cause of the onus was the Hamidian Massacres of Armenians because they were Christians, but it seemed to spill over into the protracted conflicts of the Balkans. For a time, "Near East" meant primarily the Balkans. Robert Hichens' book The Near East (1913) is subtitled Dalmatia, Greece and Constantinople.


The change is evident in the reports of influential British travellers to the Balkans. In 1894, Sir Henry Norman, 1st Baronet, a journalist, travelled to the Far East, afterwards writing a book called The Peoples and Politics of the Far East, which came out in 1895. By "Far East" he meant Siberia, China, Japan, Korea, Siam and Malaya. As the book was a big success, he was off to the Balkan states with his wife in 1896 to develop detail for a sequel, The People and Politics of the Near East, which Scribners planned to publish in 1897. Mrs. Norman, a writer herself, wrote glowing letters of the home and person of Mme. Zakki, "the wife of a Turkish cabinet minister," who, she said, was a cultivated woman living in a country home full of books. As for the natives of the Balkans, they were "a semi-civilized people."


The book was never published. Instead the Normans whirled off to New York. Norman published the gist of his planned travel book curiously mixed with vituperation against the Ottoman Empire in an article in June, 1896, in Scribner's Magazine. The empire had descended from an enlightened civilization ruling over barbarians for their own good to something considerably less. The difference was the Hamidian Massacres, which were being conducted even as the couple traveled the Balkans. According to Norman now, the empire had been established by "the Moslem horde" from Asia, which was stopped by "intrepid Hungary." Furthermore, "Greece shook off the turbaned destroyer of her people" and so on. The Russians were suddenly liberators of oppressed Balkan states. Having portrayed the Armenians as revolutionaries in the name of freedom with the expectation of being rescued by the intervention of Christian Europe, he states "but her hope was vain." England had "turned her back." Norman concluded his exhortation with "In the Balkans one learns to hate the Turk." Norman made sure that Gladstone read the article. Prince Nicolas of Montenegro wrote a letter thanking him for his article.


Throughout this article Norman uses "Near East" to mean the countries where "the eastern question" applied; that is, to all of the Balkans. The countries and regions mentioned are Greece, Bulgaria, Serbia, Bosnia-Herzegovina (which was Moslem and needed, in his view, to be suppressed), Macedonia, Montenegro, Albania, Romania. The rest of the Ottoman domain is demoted to just "the east."


If Norman was apparently attempting to change British policy, it was perhaps William Miller (1864–1945), journalist and expert on the Near East, who did the most in that direction. In essence, he signed the death warrant, so to speak, of the Age of Empires. The fall of the Ottoman Empire ultimately enmeshed all the others as well. In the Travel and Politics in the Near East, 1898, Miller claimed to have made four trips to the Balkans, 1894, 1896, 1897 and 1898, and to be, in essence, an expert on "the Near East," by which he primarily meant the Balkans. Apart from the fact that he attended Oxford and played Rugby not many biographical details have been promulgated. He was in effect (whatever his formal associations if any) a point man of British near eastern intelligence.


These were fighting words to be coming from a country that once insisted Europe needed Turkey and was willing to spill blood over it. For his authority Miller invokes the people, citing the "collective wisdom" of Europe, and introducing a concept to arise many times in the decades to follow under chilling circumstances:


If the British Empire was now going to side with the Russian Empire, the Ottoman Empire had no choice but to cultivate a relationship with the Austro-Hungarian Empire, which was supported by the German Empire. In a few years these alignments became the Triple Entente and the Triple Alliance (already formed in 1882), which were in part a cause of World War I. By its end in 1918 three empires were gone, a fourth was about to fall to revolution, and two more, the British and French, were forced to yield in revolutions started under the aegis of their own ideologies.


By 1916, when millions of Europeans were becoming casualties of imperial war in the trenches of eastern and western Europe over "the eastern question," Arnold J. Toynbee, Hegelesque historian of civilization at large, was becoming metaphysical about the Near East. Geography alone was not a sufficient explanation of the terms, he believed. If the Ottoman Empire had been a sick man, then:


From the death of the Near East new nations were able to rise from the ashes, notably the Republic of Turkey. Paradoxically it now aligned itself with the west rather than with the east. Mustafa Kemal, its founder, a former Ottoman high-ranking officer, was insistent on this social revolution, which, among other changes, liberated women from the strait rules still in effect in most Arabic-speaking countries. The demise of the political Near East now left a gap where it had been, into which stepped the Middle East.


The term middle east as a noun and adjective was common in the 19th century in nearly every context except diplomacy and archaeology. An uncountable number of places appear to have had their middle easts from gardens to regions, including the United States. The innovation of the term "Near East" to mean the holdings of the Ottoman Empire as early as the Crimean War had left a geographical gap. The East Indies, or "Far East," derived ultimately from Ptolemy's "India Beyond the Ganges." The Ottoman Empire ended at the eastern border of Iraq. "India This Side of the Ganges" and Iran had been omitted. The archaeologists counted Iran as "the Near East" because Old Persian cuneiform had been found there. This usage did not sit well with the diplomats; India was left in an equivocal state. They needed a regional term.


The use of the term Middle East as a region of international affairs apparently began in British and American diplomatic circles quite independently of each other over concern for the security of the same country: Iran, then known to the west as Persia. In 1900 Thomas Edward Gordon published an article, The Problem of the Middle East, which began:


The threat that caused Gordon, diplomat and military officer, to publish the article was resumption of work on a railway from Russia to the Persian Gulf. Gordon, a published author, had not used the term previously, but he was to use it from then on.


A second strategic personality from American diplomatic and military circles, Alfred Thayer Mahan, concerned about the naval vulnerability of the trade routes in the Persian Gulf and Indian Ocean, commented in 1902:


Apparently the sailor did not connect with the soldier, as Mahan believed he was innovating the term Middle East. It was, however, already there to be seen.


Until the period following World War I the Near East and the Middle East coexisted, but they were not always seen as distinct. Bertram Lenox Simpson, a colonial officer killed eventually in China, uses the terms together in his 1910 book, The Conflict of Color, as "the Near and Middle East." The total super-region consisted of "India, Afghanistan, Persia, Arabistan, Asia Minor, and last, but not least, Egypt." Simpson (under his pen-name, Weale) explains that this entire region "is politically one region – in spite of the divisions into which it is academically divided." His own term revives "the Nearer East" as opposed to "the Far East."


The basis of Simpson's unity is color and colonial subjection. His color chart recognizes a spectrum of black, brown and yellow, which at the time had been traditional since the late 19th century. Apart from these was "the great white race", which the moderate Simpson tones down to simply the white race. The great whites were appearing as late as the 1920s works of James Henry Breasted, which were taught as the gospel of ancient history throughout the entire first half of the 20th century. A red wavelength was mainly of interest in America. The eastern question was modified by Simpson to "The Problem of the Nearer East," which had nothing to do with the Ottomans but everything to do with British colonialism. Simpson wrote of the white man:


These regions were occupied by "the brown men," with the yellow in the Far East and the black in Africa. The color issue was not settled until Kenya became independent in 1963, ending the last vestige of the British Empire.


This view reveals a somewhat less than altruistic Christian intent of the British Empire; however, it was paradoxical from the beginning, as Simpson and most other writers pointed out. The Ottomans were portrayed as the slavers, but even as the American and British fleets were striking at the Barbary pirates on behalf of freedom, their countries were promulgating a vigorous African slave trade of their own. Charles George Gordon is known as the saint of all British colonial officers. A dedicated Christian, he spent his time between assignments living among the poor and donating his salary on their behalf. He won Ottoman confidence as a junior officer in the Crimean War. In his later career he became a high official in the Ottoman Empire, working as Governor of Egypt for the Ottoman khedive for the purpose of conducting campaigns against slavers and slavery in Egypt and the Sudan.


The term "Near and Middle East," held the stage for a few years before World War I. It proved to be less acceptable to a colonial point of view that saw the entire region as one. In 1916 Captain T.C. Fowle, 40th Pathans (troops of British India), wrote of a trip he had taken from Karachi to Syria just before the war. The book does not contain a single instance of "Near East." Instead, the entire region is considered "the Middle East." The formerly Near Eastern sections of his trip are now "Turkish" and not Ottoman.


Subsequently with the disgrace of "Near East" in diplomatic and military circles, "Middle East" prevailed. However, "Near East" continues in some circles at the discretion of the defining agency or academic department. They are not generally considered distinct regions as they were at their original definition.


Although racial and colonial definitions of the Middle East are no longer considered ideologically sound, the sentiment of unity persists. For much, but by no means all, of the Middle East, the predominance of Islam lends some unity, as does the transient accident of geographical continuity. Otherwise there is but little basis except for history and convention to lump together peoples of multiple, often unrelated languages, governments, loyalties and customs.


In the 20th century after decades of intense warfare and political turmoil terms such as "Near East", "Far East" and "Middle East" were relegated to the experts, especially in the new field of political science. The new wave of diplomats often came from those programs. Archaeology on the international scene, although very much of intellectual interest to the major universities, fell into the shadow of international relations. Their domain became the Ancient Near East, which could no longer be relied upon to be the Near East. The Ottoman Empire was gone, along with all the other empires of the 19th century, replaced with independent republics. Someone had to reconcile the present with the past. This duty was inherited by various specialized agencies that were formed to handle specific aspects of international relations, now so complex as to be beyond the scope and abilities of a diplomatic corps in the former sense. The ancient Near East is frozen in time. The living Near East is primarily what the agencies say it is. In most cases this single term is inadequate to describe the geographical range of their operations. The result is multiple definitions.


The United States is the chief remaining nation to assign official responsibilities to a region called the Near East. Within the government the State Department has been most influential in promulgating the Near Eastern regional system. The countries of the former empires of the 19th century have in general abandoned the term and the subdivision in favor of Middle East, North Africa and various forms of Asia. In many cases, such as France, no distinct regional substructures have been employed. Each country has its own French diplomatic apparatus, although regional terms, including Proche-Orient and Moyen-Orient, may be used in a descriptive sense. The most influential agencies in the United States still using Near East as a working concept are as follows.


The Bureau of Near Eastern Affairs, a division of the United States Department of State, is perhaps the most influential agency to still use the term Near East. Under the Secretary of State, it implements the official diplomacy of the United States, called also statecraft by Secretary Clinton. The name of the bureau is traditional and historic. There is, however, no distinct Middle East. All official Middle Eastern affairs are referred to this bureau.


Working closely in conjunction with the definition of the Near East provided by the State Department is the Near East South Asia Center for Strategic Studies (NESA), an educational institution of the United States Department of Defense. It teaches courses and holds seminars and workshops for government officials and military officers who will work or are working within its region. As the name indicates, that region is a combination of State Department regions; however, NESA is careful to identify the State Department region. As its Near East is not different from the State Department's it does not appear in the table. Its name, however, is not entirely accurate. For example, its region includes Mauritania, a member of the State Department's Africa (Sub-Sahara).


The Washington Institute for Near East Policy (WINEP) is a non-profit organization for research and advice on Middle Eastern policy. It regards its target countries as the Middle East but adopts the convention of calling them the Near East to be in conformance with the practices of the State Department. Its views are independent. The WINEP bundles the countries of Northwest Africa together under "North Africa." Details can be found in Policy Focus #65.


The Library of Congress (LoC) is an institution established by Congress to provide a research library for the government of the United States and serve as a national library. It is under the supervision of the United States Congress Joint Committee on the Library and the Librarian of Congress. The Near East is a separate topic and subdivision of the African and Middle Eastern division. The Middle East contains a Hebraic section consisting of only Israel for a country, but including eleven modern and ancient languages relating to Judaism, such as Yiddish, a European pidgin language. The Near East is otherwise nearly identical to the Middle East, except that it extends partly into Central Asia and the Caucasus, regions that the State Department considers to be in Asia.


The United Nations formulates multiple regional divisions as is convenient for its various operations. But few of them include a Near East, and that poorly defined. UNICEF recognizes the "Middle East and North Africa" region, where the Middle East is bounded by the Red Sea on the west and includes Iran on the east. UNESCO recognizes neither a Near East nor a Middle East, dividing the countries instead among three regions: Arab States, Asia and the Pacific, and Africa. Its division "does not forcibly reflect geography" but "refers to the execution of regional activities." The United Nations Statistics Division defines Western Asia to contain the countries included elsewhere in the Middle East. The Food and Agriculture Organization (FAO) describes its entire theatre of operations as the Near East, but then assigns many of its members to other regions as well; for example, Cyprus, Malta and Turkey are in both the European and the Near Eastern regions. Its total area extends further into Central Asia than that of most agencies.


The Central Intelligence Agency (CIA) is a quasi-independent agency of the United States Government. It appears to have multiple leadership. On the one hand its director is appointed by the president. It plays a significant role in providing the president with intelligence. On the other hand, Congress oversees its operations through a committee. The CIA was first formed under the National Security Act of 1947 from the army's Office of Strategic Services (OSS), which furnished both military intelligence and clandestine military operations to the army during the crisis of World War II. Many revisions and redefinitions have taken place since then. Although the name of the CIA reflects the original advised intent of Presidents Franklin D. Roosevelt and Harry S. Truman, the government's needs for strategic services have frustrated that intent from the beginning. The press received by the agency in countless articles, novels and other media have tended to create various popular myths; for example, that this agency replaced any intelligence effort other than that of the OSS, or that it contains the central intelligence capability of the United States. Strategic services are officially provided by some 17 agencies called the Intelligence Community. Army intelligence did not come to an end; in fact, all the branches of the Armed Forces retained their intelligence services. This community is currently under the leadership (in addition to all its other leadership) of the Office of the Director of National Intelligence.


Under these complex circumstances regional names are less useful. They are more historical than an accurate gauge of operations. The Directorate of Intelligence, one of four directorates into which the CIA is divided, includes the Office of Near Eastern and South Asian Analysis (NESA). Its duties are defined as "support on Middle Eastern and North African countries, as well as on the South Asian nations of India, Pakistan, and Afghanistan." The total range of countries is in fact the same as the State Department's Near East, but the names do not correspond. The Near East of the NESA is the same as the Middle East defined in the CIA-published on-line resource, The World Factbook. Its list of countries is limited by the Red Sea, comprises the entire eastern coast of the Mediterranean, including Israel, Turkey, the small nations of the Caucasus, Iran and the states of the Arabian Peninsula.


The U.S. Agency for International Development (USAID), an independent agency under the Department of State established in place of the Marshall Plan for the purpose of determining and distributing foreign aid, does not use the term Near East. Its definition of Middle East corresponds to that of the State Department, which officially prefers the term Near East.


The Foreign and Commonwealth Office of United Kingdom recognises a Middle East and North Africa region, but not a Near East. Their original Middle East consumed the Near East as far as the Red Sea, ceded India to the Asia and Oceania region, and went into partnership with North Africa as far as the Atlantic.


The Ministry of Foreign Affairs of the Republic of Greece conducts "bilateral relationships" with the countries of the "Mediterranean – Middle East Region" but has formulated no Near East Region. The Ministry of Foreign Affairs of the Republic of Turkey also does not use the term Near East. Its regions include the Middle East, the Balkans and others.


The Ancient Near East is a term of the 20th century intended to stabilize the geographical application of Near East to ancient history.[citation needed] The Near East may acquire varying meanings, but the Ancient Near East always has the same meaning: the ancient nations, people and languages of the enhanced Fertile Crescent, a sweep of land from the Nile Valley through Anatolia and southward to the limits of Mesopotamia.


Resorting to this verbal device, however, did not protect the "Ancient Near East" from the inroads of "the Middle East." For example, a high point in the use of "Ancient Near East" was for Biblical scholars the Ancient Near Eastern Texts relating to the Old Testament by James Bennett Pritchard, a textbook of first edition dated 1950. The last great book written by Leonard Woolley, British archaeologist, excavator of ancient Ur and associate of T.E. Lawrence and Arthur Evans, was The Art of the Middle East, Including Persia, Mesopotamia and Palestine, published in 1961. Woolley had completed it in 1960 two weeks before his death. The geographical ranges in each case are identical.


Parallel with the growth of specialized agencies for conducting or supporting statescraft in the second half of the 20th century has been the collection of resources for scholarship and research typically in university settings. Most universities teaching the liberal arts have library and museum collections. These are not new; however, the erection of these into "centres" of national and international interest in the second half of the 20th century have created larger databases not available to the scholars of the past. Many of these focus on the Ancient Near East or Near East in the sense of Ancient Near East.


One such institution is the Centre for the Study of Ancient Documents (CSAD) founded by and located centrally at Oxford University, Great Britain. Among its many activities CSAD numbers "a long-term project to create a library of digitised images of Greek inscriptions." These it arranges by region. The Egypt and the Near East region besides Egypt includes Cyprus, Persia and Afghanistan but not Asia Minor (a separate region).


A large percentage of experts on the modern Middle East began their training in university departments named for the Near East. Similarly the journals associated with these fields of expertise include the words Near East or Near Eastern. The meaning of Near East in these numerous establishments and publications is Middle East. Expertise on the modern Middle East is almost never mixed or confused with studies of the Ancient Near East, although often "Ancient Near East" is abbreviated to "Near East" without any implication of modern times. For example, "Near Eastern Languages" in the ancient sense includes such languages as Sumerian and Akkadian. In the modern sense, it is likely to mean any or all of the Arabic languages.


Zhejiang (help·info), formerly romanized as Chekiang, is an eastern coastal province of China. Zhejiang is bordered by Jiangsu province and Shanghai municipality to the north, Anhui province to the northwest, Jiangxi province to the west, and Fujian province to the south; to the east is the East China Sea, beyond which lie the Ryukyu Islands of Japan.


The province's name derives from the Zhe River (浙江, Zhè Jiāng), the former name of the Qiantang River which flows past Hangzhou and whose mouth forms Hangzhou Bay. It is usually glossed as meaning "Crooked" or "Bent River", from the meaning of Chinese 折, but is more likely a phono-semantic compound formed from adding 氵 (the "water" radical used for river names) to phonetic 折 (pinyin zhé but reconstructed Old Chinese *tet), preserving a proto-Wu name of the local Yue, similar to Yuhang, Kuaiji, and Jiang.


Zhejiang was the site of the Neolithic cultures of the Hemudu and Liangzhu. A 2007 analysis of the DNA recovered from human remains in the archeological sites of prehistoric peoples along the Yangtze River shows high frequencies of haplogroup O1 in the Liangzhu culture, linking them to Austronesian and Tai-Kadai peoples.


The area of modern Zhejiang was outside the major sphere of influence of the Shang civilization during the second millennium BC. Instead, this area was populated by peoples collectively known as the Hundred Yue, including the Dongyue and the Ouyue. The kingdom of Yue began to appear in the chronicles and records written during the Spring and Autumn Period. According to the chronicles, the kingdom of Yue was located in northern Zhejiang. Shiji claims that its leaders were descended from the Shang founder Yu the Great. Evidence suggests that Baiyue and the kingdom of Yue possessed their own culture and history that are different from those kingdoms in north and central China, whose cultures and histories were carefully recorded in chronicles and histories during the Spring and Autumn Period and into the Qin dynasty. The Song of the Yue Boatman (Chinese: 越人歌, p Yuèrén Gē, lit. "Song of the man of Yue") was transliterated into Chinese and recorded by authors in north China or inland China of Hebei and Henan around 528 BC. The song shows that the Yue people spoke a language that was mutually unintelligible with the dialects spoken in north and inland China. The Yue peoples seem to have had their own written script. The Sword of Goujian bears bird-worm seal script. Yuenü (Chinese: 越女; pinyin: Yuènǚ; Wade–Giles: Yüeh-nü; literally: "the Lady of Yue") was a swordswoman from the state of Yue. In order to check the growth of the kingdom of Wu, Chu pursued a policy of strengthening Yue. Under King Goujian, Yue recovered from its early reverses and fully annexed the lands of its rival in 473 BC. The Yue kings then moved their capital center from their original home around Mount Kuaiji in present-day Shaoxing to the former Wu capital at present-day Suzhou. With no southern power to turn against Yue, Chu opposed it directly and, in 333 BC, succeeded in destroying it. Yue's former lands were annexed by the Qin Empire in 222 BC and organized into a commandery named for Kuaiji in Zhejiang but initially headquartered in Wu in Jiangsu.


Kuaiji Commandery was the initial power base for Xiang Liang and Xiang Yu's rebellion against the Qin Empire which initially succeeded in restoring the kingdom of Chu but eventually fell to the Han. Under the Later Han, control of the area returned to the settlement below Mount Kuaiji but authority over the Minyue hinterland was nominal at best and its Yue inhabitants largely retained their own political and social structures.


At the beginning of the Three Kingdoms era (220–280 CE), Zhejiang was home to the warlords Yan Baihu and Wang Lang prior to their defeat by Sun Ce and Sun Quan, who eventually established the Kingdom of Wu. Despite the removal of their court from Kuaiji to Jianye (present-day Nanjing), they continued development of the region and benefitted from influxes of refugees fleeing the turmoil in northern China. Industrial kilns were established and trade reached as far as Manchuria and Funan (south Vietnam).


Zhejiang was part of the Wu during the Three Kingdoms. Wu (229–280), commonly known as Eastern Wu or Sun Wu, had been the economically most developed state among the Three Kingdoms (220–280 CE). The historical novel Romance of the Three Kingdoms records that Zhejiang had the best-equipped, strong navy force. The story depicts how the states of Wei (魏) and Shu (蜀), lack of material resources, avoided direct confrontation with the Wu. In armed military conflicts with Wu, the two states relied intensively on tactics of camouflage and deception to steal Wu's military resources including arrows and bows.


Despite the continuing prominence of Nanjing (then known as Jiankang), the settlement of Qiantang, the former name of Hangzhou, remained one of the three major metropolitan centers in the south to provide major tax revenue to the imperial centers in the north China. The other two centers in the south were Jiankang and Chengdu. In 589, Qiangtang was raised in status and renamed Hangzhou.


Following the fall of Wu and the turmoil of the Wu Hu uprising against the Jin dynasty (265–420), most of elite Chinese families had collaborated with the non-Chinese rulers and military conquerors in the north. Some may have lost social privilege, and took refugee in areas south to Yangtze River. Some of the Chinese refugees from north China might have resided in areas near Hangzhou. For example, the clan of Zhuge Liang (181–234), a chancellor of the state of Shu Han from Central Plain in north China during the Three Kingdoms period, gathered together at the suburb of Hangzhou, forming an exclusive, closed village Zhuge Village (Zhege Cun), consisting of villagers all with family name "Zhuge". The village has intentionally isolated itself from the surrounding communities for centuries to this day, and only recently came to be known in public. It suggests that a small number of powerful, elite Chinese refugees from the Central Plain might have taken refugee in south of the Yangtze River. However, considering the mountainous geography and relative lack of agrarian lands in Zhejiang, most of these refugees might have resided in some areas in south China beyond Zhejiang, where fertile agrarian lands and metropolitan resources were available, mainly north Jiangsu, west Fujian, Jiangxi, Hunan, Anhui,and provinces where less cohesive, organized regional governments had been in place. Metropolitan areas of Sichuan was another hub for refugees, given that the state of Shu had long been founded and ruled by political and military elites from the Central Plain and north China. Some refugees from the north China might have found residence in south China depending on their social status and military power in the north. The rump Jin state or the Southern Dynasties vied against some elite Chinese from the Central Plain and south of the Yangtze River.


Zhejiang, as the heartland of the Jiangnan (Yangtze River Delta), remained the wealthiest area during the Six Dynasties (220 or 222–589), Sui, and Tang. After being incorporated into the Sui dynasty, its economic richness was used for the Sui dynasty's ambitions to expand north and south, particularly into Korea and Vietnam. The plan led the Sui dynasty to restore and expand the network which became the Grand Canal of China. The Canal regularly transported grains and resources from Zhejiang, through its metropolitan center Hangzhou (and its hinterland along both the Zhe River and the shores of Hangzhou Bay), and from Suzhou, and thence to the North China Plain. The débâcle of the Korean war led to Sui's overthrow by the Tang, who then presided over a centuries-long golden age for the country. Zhejiang was an important economic center of the empire's Jiangnan East Circuit and was considered particularly prosperous. Throughout the Tang dynasty, The Grand Canal had remained effective, transporting grains and material resources to North China plain and metropolitan centers of the empire. As the Tang Dynasty disintegrated, Zhejiang constituted most of the territory of the regional kingdom of Wuyue.


The Song dynasty reëstablished unity around 960. Under the Song, the prosperity of South China began to overtake that of North China. After the north was lost to the Jurchen Jin dynasty in 1127 following the Jingkang Incident, Hangzhou became the capital of the Southern Song under the name Lin'an. Renowned for its prosperity and beauty, it may have been the largest city in the world at the time. From then on, north Zhejiang and neighboring south Jiangsu have been synonymous with luxury and opulence in Chinese culture. The Mongol conquest and the establishment of the Yuan dynasty in 1279 ended Hangzhou's political clout, but its economy continued to prosper. Marco Polo visited the city, which he called "Kinsay" (after the Chinese Jingshi, meaning "Capital City") claiming it was "the finest and noblest city in the world".


Greenware ceramics made from celadon had been made in the area since the 3rd-century Jin dynasty, but it returned to prominence—particularly in Longquan—during the Southern Song and Yuan. Longquan greenware is characterized by a thick unctuous glaze of a particular bluish-green tint over an otherwise undecorated light-grey porcellaneous body that is delicately potted. Yuan Longquan celadons feature a thinner, greener glaze on increasingly large vessels with decoration and shapes derived from Middle Eastern ceramic and metalwares. These were produced in large quantities for the Chinese export trade to Southeast Asia, the Middle East, and (during the Ming) Europe. By the Ming, however, production was notably deficient in quality. It is in this period that the Longquan kilns declined, to be eventually replaced in popularity and ceramic production by the kilns of Jingdezhen in Jiangxi.


"In 1727 the to-min or 'idle people' of Cheh Kiang province (a Ningpo name still existing), the yoh-hu or 'music people' of Shanxi province, the si-min or 'small people' of Kiang Su (Jiangsu) province, and the Tanka people or 'egg-people' of Canton (to this day the boat population there), were all freed from their social disabilities, and allowed to count as free men." "Cheh Kiang" is another romanization for Zhejiang. The Duomin (Chinese: 惰民; pinyin: duò mín; Wade–Giles: to-min) are a caste of outcasts in this province.


During the First Opium War, the British navy defeated Eight Banners forces at Ningbo and Dinghai. Under the terms of the Treaty of Nanking, signed in 1843, Ningbo became one of the five Chinese treaty ports opened to virtually unrestricted foreign trade. Much of Zhejiang came under the control of the Taiping Heavenly Kingdom during the Taiping Rebellion, which resulted in a considerable loss of life in the province. In 1876, Wenzhou became Zhejiang's second treaty port.


During the Second Sino-Japanese War, which led into World War II, much of Zhejiang was occupied by Japan and placed under the control of the Japanese puppet state known as the Reorganized National Government of China. Following the Doolittle Raid, most of the B-25 American crews that came down in China eventually made it to safety with the help of Chinese civilians and soldiers. The Chinese people who helped them, however, paid dearly for sheltering the Americans. The Imperial Japanese Army began the Zhejiang-Jiangxi Campaign to intimidate the Chinese out of helping downed American airmen. The Japanese killed an estimated 250,000 civilians while searching for Doolittle’s men.


After the People's Republic of China took control of Mainland China in 1949, the Republic of China government based in Taiwan continued to control the Dachen Islands off the coast of Zhejiang until 1955, even establishing a rival Zhejiang provincial government there, creating a situation similar to Fujian province today. During the Cultural Revolution (1966–76), Zhejiang was in chaos and disunity, and its economy was stagnant, especially during the high tide (1966–69) of the revolution. The agricultural policy favoring grain production at the expense of industrial and cash crops intensified economic hardships in the province. Mao’s self-reliance policy and the reduction in maritime trade cut off the lifelines of the port cities of Ningbo and Wenzhou. While Mao invested heavily in railroads in interior China, no major railroads were built in South Zhejiang, where transportation remained poor.


Zhejiang benefited less from central government investment than some other provinces due to its lack of natural resources, a location vulnerable to potential flooding from the sea, and an economic base at the national average. Zhejiang, however, has been an epicenter of capitalist development in China, and has led the nation in the development of a market economy and private enterprises. Northeast Zhejiang, as part of the Yangtze Delta, is flat, more developed, and industrial.


Zhejiang consists mostly of hills, which account for about 70% of its total area. Altitudes tend to be the highest to the south and west and the highest peak of the province, Huangmaojian Peak (1,929 meters or 6,329 feet), is located there. Other prominent mountains include Mounts Yandang, Tianmu, Tiantai, and Mogan, which reach altitudes of 700 to 1,500 meters (2,300 to 4,900 ft).


Valleys and plains are found along the coastline and rivers. The north of the province lies just south of the Yangtze Delta, and consists of plains around the cities of Hangzhou, Jiaxing, and Huzhou, where the Grand Canal of China enters from the northern border to end at Hangzhou. Another relatively flat area is found along the Qu River around the cities of Quzhou and Jinhua. Major rivers include the Qiangtang and Ou Rivers. Most rivers carve out valleys in the highlands, with plenty of rapids and other features associated with such topography. Well-known lakes include the West Lake of Hangzhou and the South Lake of Jiaxing.


There are over three thousand islands along the rugged coastline of Zhejiang. The largest, Zhoushan Island, is Mainland China's third largest island, after Hainan and Chongming. There are also many bays, of which Hangzhou Bay is the largest.  Zhejiang has a humid subtropical climate with four distinct seasons. Spring starts in March and is rainy with changeable weather. Summer, from June to September is long, hot, rainy, and humid. Fall is generally dry, warm and sunny. Winters are short but cold except in the far south. Average annual temperature is around 15 to 19 °C (59 to 66 °F), average January temperature is around 2 to 8 °C (36 to 46 °F) and average July temperature is around 27 to 30 °C (81 to 86 °F). Annual precipitation is about 1,000 to 1,900 mm (39 to 75 in). There is plenty of rainfall in early summer, and by late summer Zhejiang is directly threatened by typhoons forming in the Pacific.


The eleven prefecture-level divisions of Zhejiang are subdivided into 90 county-level divisions (36 districts, 20 county-level cities, 33 counties, and one autonomous county). Those are in turn divided into 1,570 township-level divisions (761 towns, 505 townships, 14 ethnic townships, and 290 subdistricts). Hengdian belongs to Jinhua, which is the largest base of shooting films and TV dramas in China. Hengdian is called "China's Hollywood".


The politics of Zhejiang is structured in a dual party-government system like all other governing institutions in Mainland China. The Governor of Zhejiang is the highest-ranking official in the People's Government of Zhejiang. However, in the province's dual party-government governing system, the Governor is subordinate to the Zhejiang Communist Party of China (CPC) Provincial Committee Secretary, colloquially termed the "Zhejiang CPC Party Chief".


Several political figures who served as Zhejiang's top political office of Communist Party Secretary have played key roles in various events in PRC history. Tan Zhenlin (term 1949-1952), the inaugural Party Secretary, was one of the leading voices against Mao's Cultural Revolution during the so-called February Countercurrent of 1967. Jiang Hua (term 1956-1968), was the "chief justice" on the Special Court in the case against the Gang of Four in 1980. Three provincial Party Secretaries since the 1990s have gone onto prominence at the national level. They include CPC General Secretary and President Xi Jinping (term 2002-2007), National People's Congress Chairman and former Vice-Premier Zhang Dejiang (term 1998-2002), and Zhao Hongzhu (term 2007-2012), the Deputy Secretary of the Central Commission for Discipline Inspection, China's top anti-corruption body. Of Zhejiang's fourteen Party Secretaries since 1949, none were native to the province.


The province is traditionally known as the "Land of Fish and Rice". True to its name, rice is the main crop, followed by wheat; north Zhejiang is also a center of aquaculture in China, and the Zhoushan fishery is the largest fishery in the country. The main cash crops include jute and cotton, and the province also leads the provinces of China in tea production. (The renowned Longjing tea is a product of Hangzhou.) Zhejiang's towns have been known for handicraft production of goods such as silk, for which it is ranked second among the provinces. Its many market towns connect the cities with the countryside.


Ningbo, Wenzhou, Taizhou and Zhoushan are important commercial ports. The Hangzhou Bay Bridge between Haiyan County and Cixi, is the longest bridge over a continuous body of sea water in the world.


Zhejiang's main manufacturing sectors are electromechanical industries, textiles, chemical industries, food, and construction materials. In recent years Zhejiang has followed its own development model, dubbed the "Zhejiang model", which is based on prioritizing and encouraging entrepreneurship, an emphasis on small businesses responsive to the whims of the market, large public investments into infrastructure, and the production of low-cost goods in bulk for both domestic consumption and export. As a result, Zhejiang has made itself one of the richest provinces, and the "Zhejiang spirit" has become something of a legend within China. However, some economists now worry that this model is not sustainable, in that it is inefficient and places unreasonable demands on raw materials and public utilities, and also a dead end, in that the myriad small businesses in Zhejiang producing cheap goods in bulk are unable to move to more sophisticated or technologically more advanced industries. The economic heart of Zhejiang is moving from North Zhejiang, centered on Hangzhou, southeastward to the region centered on Wenzhou and Taizhou. The per capita disposable income of urbanites in Zhejiang reached 24,611 yuan (US$3,603) in 2009, an annual real growth of 8.3%. The per capita pure income of rural residents stood at 10,007 yuan (US$1,465), a real growth of 8.1% year-on-year. Zhejiang's nominal GDP for 2011 was 3.20 trillion yuan (US$506 billion) with a per capita GDP of 44,335 yuan (US$6,490). In 2009, Zhejiang's primary, secondary, and tertiary industries were worth 116.2 billion yuan (US$17 billion), 1.1843 trillion yuan (US$173.4 billion), and 982.7 billion yuan (US$143.9 billion) respectively.


On Thursday, September 15, 2011, more than 500 people from Hongxiao Village protested over the large-scale death of fish in a nearby river. Angry protesters stormed the Zhejiang Jinko Solar Company factory compound, overturned eight company vehicles, and destroyed the offices before police came to disperse the crowd. Protests continued on the two following nights with reports of scuffles, officials said. Chen Hongming, a deputy head of Haining's environmental protection bureau, said the factory's waste disposal had failed pollution tests since April. The environmental watchdog had warned the factory, but it had not effectively controlled the pollution, Chen added.


Han Chinese make up the vast majority of the population, and the largest Han subgroup are the speakers of Wu varieties of Chinese. There are also 400,000 members of ethnic minorities, including approximately 200,000 She people and approximately 20,000 Hui Chinese[citation needed]. Jingning She Autonomous County in Lishui is the only She autonomous county in China.


The predominant religions in Zhejiang are Chinese folk religions, Taoist traditions and Chinese Buddhism. According to surveys conducted in 2007 and 2009, 23.02% of the population believes and is involved in cults of ancestors, while 2.62% of the population identifies as Christian, decreasing from 3.92% in 2004. The reports didn't give figures for other types of religion; 74.36% of the population may be either irreligious or involved in worship of nature deities, Buddhism, Confucianism, Taoism, folk religious sects, and small minorities of Muslims.


In mid-2015 the government of Zhejiang recognised folk religion as "civil religion" beginning the registration of more than twenty thousand folk religious associations. Buddhism has an important presence since its arrival in Zhejiang 1,800 years ago.


Catholicism arrived 400 years ago in the province and Protestantism 150 years ago. Zhejiang is one of the provinces of China with the largest concentrations of Protestants, especially notable in the city of Wenzhou. In 1999 Zhejiang's Protestant population comprised 2.8% of the provincial population, a small percentage but higher than the national average.


The rapid development of religions in Zhejiang has driven the local committee of ethnic and religious affairs to enact measures to rationalise them in 2014, variously named "Three Rectifications and One Demolition" operations or "Special Treatment Work on Illegally Constructed Sites of Religious and Folk Religion Activities" according to the locality. These regulations have led to cases of demolition of churches and folk religion temples, or the removal of crosses from churches' roofs and spires. An exemplary case was that of the Sanjiang Church.


Islam arrived 1,400 years ago in Zhejiang. Today Islam is practiced by a small number of people including virtually all the Hui Chinese living in Zhejiang. Another religion present in the province is She shamanism (practiced by She ethnic minority).


Zhejiang is mountainous and has therefore fostered the development of many distinct local cultures. Linguistically speaking, Zhejiang is extremely diverse. Most inhabitants of Zhejiang speak Wu, but the Wu dialects are very diverse, especially in the south, where one valley may speak a dialect completely unintelligible to the next valley a few kilometers away. Other varieties of Chinese are spoken as well, mostly along the borders; Mandarin and Huizhou dialects are spoken on the border with Anhui, while Min dialects are spoken on the border with Fujian. (See Hangzhou dialect, Shaoxing dialect, Ningbo dialect, Wenzhou dialect, Taizhou dialect, Jinhua dialect, and Quzhou dialect for more information).


Throughout history there have been a series of lingua francas in the area to allow for better communication. The dialects spoken in Hangzhou, Shaoxing, and Ningbo have taken on this role historically. Since the founding of the People's Republic of China in 1949, Mandarin, which is not mutually intelligible with any of the local dialects, has been promoted as the standard language of communication throughout China. As a result, most of the population now can, to some degree, speak and comprehend Mandarin and can code-switch when necessary. A majority of the population educated since 1978 can speak Mandarin. Urban residents tend to be more fluent in Mandarin than rural people. Nevertheless, a Zhejiang accent is detectable in almost everyone from the area communicating in Mandarin, and the home dialect remains an important part of the everyday lives and cultural identities of most Zhejiang residents.


Zhejiang is the home of Yueju (越劇), one of the most prominent forms of Chinese opera. Yueju originated in Shengzhou and is traditionally performed by actresses only, in both male and female roles. Other important opera traditions include Yongju (of Ningbo), Shaoju (of Shaoxing), Ouju (of Wenzhou), Wuju (of Jinhua), Taizhou Luantan (of Taizhou) and Zhuji Luantan (of Zhuji).


Longjing tea (also called dragon well tea), originating in Hangzhou, is one of the most prestigious, if not the most prestigious Chinese tea. Hangzhou is also renowned for its silk umbrellas and hand fans. Zhejiang cuisine (itself subdivided into many traditions, including Hangzhou cuisine) is one of the eight great traditions of Chinese cuisine.