People are fascinated by human evil. ​ Newspapers thrive on stories of horror and cruelty. The old saying in the press is “If it bleeds it leads”. Thrillers that depict the stories of mass murderers and serial killers fly off the shelves. TV series recounting the deeds of the worst killers and sadists in history entertain some of us for our evening viewing. It is fairly obvious that most people have an interest in this kind of human evil. However, this type of evil is only a small fraction of the evil that occurs in the world. The great insight in the work of philosopher Hannah Arendt is that most evil is committed by people who never decided to be good or bad. Therefore, if we are to discover something about human evil, we must figure out how ordinary people end up doing evil. Psychologists have largely answered why bad people do evil, but an even more important question is why do good people do evil. Answering this question is the key to understanding mass evil, genocide, and in fact most of the evil that happens in the world. This is also the question that this book “The Path to Mass Evil” seeks to answer.