This document provides a summary of world history from prehistoric times through 600 CE. It discusses early nomadic societies and the Neolithic Revolution that led to agricultural societies centered around rivers in Mesopotamia, Egypt, and the Indus Valley. These early civilizations developed complex social hierarchies, religious beliefs, and technologies. Mesopotamian civilizations included Sumer, Akkad, Babylon, and Assyria. Egyptian civilization was divided into three kingdoms and made significant achievements. The Indus Valley civilization centered around the cities of Harappa and Mohenjo-Daro before the arrival of the Aryans in India.