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.
Lesson Summary. Johannes Gutenberg was a German blacksmith and inventor known for developing the first mechanical moveable type printing press. Gutenberg was born in Mainz, Germany, around 1400. His printing press is one of the most important inventions of human history and widely considered the most important invention of the modern era.