Draws on the work of modern economic geographers to explore how the river-based ecology and geography of the Tigris-Euphrates alluvium impacted the development of urban civilization in southern Mesopotamia.

As southern polities grew in scale and complexity throughout the fourth millennium, revolutionary new forms of labor organization and record keeping were created, and it is these socially created innovations, Algaze argues, that ultimately account for why fully developed city-states emerged earlier in southern Mesopotamia than elsewhere in Southwest Asia or the world.