Clay tablets were used in Mesopotamia in the 3rd millennium BC. The calamus, an instrument in the form of a triangle, was used to make characters in moist clay. People used to use fire to dry the tablets out. At Nineveh, over 20,000 tablets were found, dating from the 7th century BC; this was the archive and library of the kings of Assyria, who had workshops of copyists and conservationists at their disposal. This presupposes a degree of organization with respect to books, consideration given to conservation, classification, etc. Tablets were used right up until the 19th century in various parts of the world, including Germany, Chile, Philippines and the Saharan Desert.
Cuneiform and Sumerian Writing
Writing originated as a form of record keeping in Sumer during the fourth millennium BCE with the advent of cuneiform. Many clay tablets have been found that show cuneiform writing used to record legal contracts, create lists of assets, and eventually to record Sumerian literature and myths. Scribal schools have been found by archaeologists from as early as the second millennium BCE where students were taught the art of writing.