H. Welzer, a well-known German social psychologist, studies the motivation of Nazi criminals of mid- and lower ranks. It is often assumed that the killers of that era had an innate inclination toward evil deeds. However, Welzer focuses on social causes, examining a combination of historical, political, and socio-psychological factors that led to the shift in moral norms in Germany and, ultimately, to mass support for Nazi genocide. This research is about how people develop readiness to kill. The author studies many archival documents to understand how mass murder became routine work for people who had previously been ordinary. In the audiobook, episodes of genocide during the Second World War are analyzed, as well as events that took place during conflicts in Vietnam, Rwanda, and the Balkans.