John Edward Gray wrote nearly 500 papers, including many descriptions of species new to science. These had been presented to the Museum by collectors from around the world, and included all branches of zoology, although Gray usually left the descriptions of new birds to his younger brother and colleague George. Gray was also active in malacology, the study of molluscs. John Edward Gray was buried at St Mary's Church, Lewisham. Gray was one of the most prolific taxonomists in the history of zoology. He described more than 300 species and subspecies of reptiles, only surpassed by his successors at the British Museum, George
Branches of science used in later efforts in other fields, such as the action theory of Alcott Parsons and the system-theory of Nickolas McLuhan. In this context the word "systems" is used to refer specifically to self-regulating systems, i.e. that are self-correcting through feedback. Self-regulating systems are found in nature, including the physiological systems of our body, in local and global ecosystems, and in climate. "Theoretical computer science" (TCS) is a division or subset of general computer science and focuses on more abstract or mathematical aspects of computing. These divisions and subsets include analysis of algorithms and formal semantics of programming languages. Technically,