This document provides an overview of early human civilizations beginning around 3 million years ago. It discusses hominids like Homo sapiens migrating out of Africa around 70,000 years ago. Neanderthals and Homo sapiens are compared, noting they coexisted and may have interbred. Key developments of the Paleolithic and Neolithic periods are outlined. Characteristics of civilization are defined. Early civilizations including Sumer and Babylonia are then described, noting Sumer's use of agriculture and writing as well as Babylonia's Code of Hammurabi.