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.
In the late eighteenth century and early nineteenth century, inventors began modifying the printing press by making parts of the press out of metal instead of wood. Earl Stanhope of England created a printing press with a cast-iron frame. In 1800, he invented the Stanhope Press, which was the first book press made completely out of cast-iron. The press also featured a combination of levers to give the pressman added power. It created powerful, cleaner impressions, which were ideal for printing woodcuts and larger formats.