How do radical religious sects run such deadly terrorist organizations? Hezbollah, Hamas, Lashkar-e-Taiba, and the Taliban all began as religious groups dedicated to piety and charity. Yet once they turned to violence, they became horribly potent, executing campaigns of terrorism deadlier than those of their secular rivals. In Radical, Religious, and Violent, Eli Berman approaches the question using the economics of organizations. He first dispels some myths: radical religious terrorists are not generally motivated by the promise of rewards in the afterlife (including the infamous seventy-two virgins) or even by religious ideas in general. He argues that these terrorists (even suicide terrorists) are best understood as rational altruists seeking to help their own communities.