In a talk sharing a title with his forthcoming book, Professor Atran made the case for scientific anthropological field research directed toward understanding the reasons behind an individual’s decision to commit terrorist violence. Current policies by governments, intended to anticipate and respond to the threat of terrorist violence, are hampered by a lack of understanding of the social pathways to violent extremism. A central puzzle is why, of the many millions who sympathize with, for instance, the jihadi cause, only a very tiny proportion demonstrate an active willingness to commit violence. Professor Atran offered a number of case studies of the process by which individuals are recruited into violent extremism, examining the role of networks of friendship and kin within contexts of neighborhoods, schools, workplaces, and leisure activity.