This chapter provides a wide-ranging analysis of the archaeological evidence for intergroup peaceful cooperation and intergroup conflict – both lethal and non-lethal – among prehistoric hunter-gatherers across world regions. It first considers evidence of peaceful group interactions, in the form of long-distance networks of exchange. It then examines the prehistoric archaeological evidence for interpersonal and intergroup conflict (lethal and non-lethal) in Africa, southwest Asia, Europe, southeast Asia and Australia, northeast Asia, and the Americas based on four sources: human skeletal remains, defensive structures, weapons, and rock art.

The Introduction sets out the central question that this book aims to tackle: when, why, and how did we evolve the peculiar and paradoxical inclination for both war and peace that characterises our species? The book argues that the inclination for both intergroup coalitionary killing and peaceful cooperation have deep roots and that they co-evolved through a gradual, incremental trajectory over millions of years. This co-evolution unfolded in a mosaic-like pattern, with distinct but interacting components emerging at different moments and becoming integrated over evolutionary time.