The authors, professionals in the field of political psychology, document and interpret the malign power of paranoia in a variety of contexts - in political movements like McCarthyism; in organizations like the John Birch Society; in leaders like Hitler, Stalin, Pol Pot, Jim Jones, and David Koresh; and among extreme groups that commit violence in the name of Christianity, Islam, and Judaism. The authors show that the paranoid dynamic has been aggressively present in every social disaster of this century. This book describes the paranoid personality, explain why paranoia is part of human evolutionary history, and examine the conditions that must exist before the message of the paranoid takes root in a vulnerable population, leading to mass movements and genocidal violence.