In order to gain social worker certification and become eligible to work in the field, individuals must earn at least a Bachelor of Science or Bachelor of Arts. A master's degree in social work is usually required for state licensure as a clinical social worker. Some programs offer training in specialized fields.
View full size image. Johannes Gutenberg is usually cited as the inventor of the printing press. Indeed, the German goldsmith's 15th-century contribution to the technology was revolutionary â enabling the mass production of books and the rapid dissemination of knowledge throughout Europe.efore the invention of the printing press â sometime between 1440 and 1450 â most European texts were printed using xylography, a form of woodblock printing similar to the Chinese method used to print The Diamond Sutra in 868.
Johannes Gutenberg was a German blacksmith known for inventing the mechanical movable type printing press. His printing press has been widely considered the most important invention of the modern era because it profoundly impacted the transmission of knowledge. Invented around 1439, Gutenberg's movable type printing press initiated nothing less than a revolution in print technology.