Cuneiform
The Sumerians are the ones credited with inventing the first form of writing, cuneiform. Merchants used this to regulate their prices, and they created a calendar based on the phases of the moon with 12 months and leap years. The writing on the tablets to the left are simple pictures, or pictograms, that represent an object or an idea. Because it is so hard to draw curved lines in clay, the Sumerians eventually reduced the pictograms into a series of wedge shaped signs. The adapted wedge - shaped signs is what we now know at cuneiform. The invention of this writing was the dawn of the Information Revolution. It allowed news and messages o be carried accross long distances without the error of human memory. It emerged because tehre was a need for it. It helped keep record of administrative procedures, and some were used as "copy books" to train future scribes. Eventually it created some of the best literary works in recorded history.
This is a video showing some basic translations of cuneiform, and how they used it in trade.