Lonnie Athens was raised in a violent world. His father was a hot-tempered man who shot at strangers and beat his wife and literally bashed his sons’ heads together. So when Athens began studying for his doctorate in criminology at the University of California, Berkeley, it was only natural that he was fascinated with the question of what makes people violent. He decided to conduct in-depth interviews with several hundred violent prison inmates, an endeavor which spanned a decade and reaped the discovery of “violentization,” the four-stage process by which almost any person, regardless of race, gender, genetic heritage, or socioeconomic status, can become someone who will assault, batter, rape, mutilate, or murder another human being.

Richard Rhodes—whose The Making of the Atomic Bomb garnered all of the major book awards—traces Athens’s journey into the fiercest corners of our world’s most brutal souls and has produced an indispensable book for anyone who has wondered why people become violent and what we can do about it. Part biography, part sociology, part intellectual history, Why They Kill is as fascinating as it insightful, as unflinching as it is wise.