Writing was probably as important as agriculture in the evolution of civilization. While agriculture freed us of the continuous hunt for food, writing enabled us to record the thought and progress we made in the time made free by agriculture.
Writing began with the start of Sumerian civilization, which lasted from 3000 B.C. to 2000 B.C.
Writing had been preceded with the invention of cylinder seals, on which little pictures were incised to be rolled on to clay; pottery may have degenerated, but these seals were one of the great Mesopotamian artistic achievements. The earliest writings are in the form of pictograms or simplified pictures (a step towards non-representative communication), on clay tablets usually baked after they had been inscribed with a reed stalk. The earliest are in Sumerian and it can be seen that they are memoranda, list of goods, receipts; their emphasis is economic and they cannot be read as continuous prose. The writing on these early notebooks and ledgers evolved slowly towards cuneiform, a way of arranging impressions stamped on clay by the wedge-like section of a chopped-off reed. With this the break with the pictogram form is complete. Signs and groups of signs come at this stage to stand for phonetic and possibly syllabic elements and are all made up of combinations of the same basic wedge shape. It was more flexible as a form of communication by signs than anything used hitherto and Sumer reached it soon after 3000 B.C.