Hammurabi of Babylon
About 1700 BC, a new king in the Mesopotamian city of Babylon managed to pull all the scattered cities back together into one empire: the Babylonian Empire. His name was Hammurabi; this is an Amorite name, so Hammurabi was probably descended from Amorite ancestors. This is another episode in what is becoming a regular West Asian cycle of empires forming under a strong ruler, gradually weakening and finally collapsing into a bunch of independent cities, and then new empires forming again under a new ruler a little later.
The code of Hammurabi in the Louvre, Paris
Hammurabi (ham-oor-AH-bee) was very concerned to do things that would bring everyone in his empire together, and make them all feel like they were part of this new project together. One thing he did was to issue a law code that would be the same for all the people in the Babylonian Empire. This is called the Code of Hammurabi, and we still have copies of it: there is a picture of it here, showing Hammurabi at the top (standing) and getting the laws from the god (sitting down). Underneath them, in tiny cuneiform writing, are all the laws.
Under Hammurabi, the Babylonian Empire was very strong, but under his children and grandchildren the empire got weaker, until eventually it collapsed like other West Asian empires.
Find Out About Mesopotamia: What Life Was Like in Ancient Sumer, Babylon and Assyria, by Lorna Oakes (2004).
Ancient Mesopotamians, by Elena Gambino (2000). Retellings of Mesopotamian stories and lots of context.
Ancient Egyptians and Their Neighbors: An Activity Guide, by Marian Broida (1999). Not just Egypt! Includes activities about the Sumerians, the Babylonians, the Hittites, and the Nubians.
Babylonians, by Henry Saggs (2000). Also includes information about the Sumerians and Akkadians.
Ancient Near Eastern History and Culture, by William H. Stiebing (2002). Expensive, and hard to read, but it's a good up to date account.
Or check out this article on Hammurabi in the Encyclopedia Britannica.