Who developed 'Cuneiform', a system of writing?

Cuneiform is a system of writing first developed by the ancient Sumerians of Mesopotamia c. 3500-3000 BCE. It is considered the most significant among the many cultural contributions of the Sumerians and the greatest among those of the Sumerian city of Uruk which advanced the writing of cuneiform c. 3200 BCE. The name comes from the Latin word 'cuneus' for 'wedge' owing to the wedge-shaped style of writing.

In Cuneiform, a carefully cut writing implement known as a stylus is pressed into soft clay to produce wedge-like impressions that represent word-signs (pictographs) and, later, phonograms or `word-concepts' (closer to a modern day understanding of a 'word' ). All the great Mesopotamian civilizations used Cuneiform (the Sumerians, Akkadians, Babylonians, Elamites, Hatti, Hittites, Assyrians, Hurrians and others) until it was abandoned in favour of the alphabetic script at some point after 100 BCE.