Writing was first developed in Mesopotamia around 3100 BCE, 1400 years before the rule of Hammurabi.  The Sumerians were the first civilization to develop a system of writing.  Sumerians found that they needed to keep records, and writing met this need.  The earliest writings we have from Sumerians are records of farm animals.  Only a few people had the skill of writing so it became a very valuable profession, one of the most coveted in the ancient world.  

Scribes, or professional writers, of Sumer recorded sales and trades, tax payments, gifts for the gods,  deaths and marriages.  Military scribes would calculate the amount of food and supplies that an army might need and government scribes would calculate how many  workers would be needed for a public project.  None of these records were written on paper, they were kept on clay tablets because paper had yet to be invented.

The Tigris and Euphrates rivers provided the clay for tablets used by scribes.  Each spring the rivers would bring clay deposits down from the mountains and the scribes would then shape the clay into smooth flat tablets for recording and writing.  When the clay dried it would become a permanent record.  Larger table size tablets would stay in one place and typically contained information that would be in today's atlases and dictionaries.  Smaller tablets could be used for more personal messages.

Writing developed over time.  The Sumerians originally used a system of tokens with symbols on them to keep records.  Eventually this form of record keeping evolved into writing.  The first written languages are symbols that represent certain words or ideas.  Examples of these could be grain, water, stars, or animals, each important object had its own symbol.  Scribes combined the symbols to make groups of wedges and lines known as cuneiform.  Cuneiform could eventually represent meaning for multiple languages and was useful to many people in many different regions.

The symbols developed over time, though most historians and scholars believe the Sumerians did not take any influence from other groups when it came to developing this system of writing.  Because of this independent growth of written language the Sumerians made major decisions on how cuneiform would be written and read.  The symbols would be in set rows, read from left to right, and from top to bottom.