Why do people go to war? Is it rooted in human nature or is it a late cultural invention? How does war relate to the other fundamental developments in the history of human civilization? And what of war today - is it a declining phenomenon or simply changing its shape? In this truly global study of war and civilization, Azar Gat sets out to find definitive answers to these questions in an attempt to unravel the 'riddle of war' throughout human history, from the early hunter- gatherers right through to the unconventional terrorism of the twenty- first century. In the process, the book generates an astonishing wealth of original and fascinating insights on all major aspects of humankind's remarkable journey through the ages, engaging a wide range of disciplines, from anthropology and evolutionary psychology to sociology and political science. Written with remarkable verve and clarity and wholly free from jargon, it will be of interest to anyone who has ever pondered the puzzle of war.