I received my Ph.D. in psychology at Stanford in 1965, started my work life as a professor at Harvard, and almost immediately began to focus on the topics of this book: goodness and evil. For many years, I have conducted research on, extensively written about, and more and more applied to the real world the understanding that is presented in this book on a variety of interrelated questions: What leads children and adults to be generous and helpful, and what leads them to respond to someone's urgent need in an emergency rather than remain passive bystanders? Why do children and adolescents bully, harass, and intimidate each other, and what can we do about it? What influences lead people, especially young people, to become aggressive and violent, and what socialization and experience in the home and school lead children and youth to become caring and helpful? What leads groups of people to engage in violent actions, especially in extreme forms of violence such as genocide and mass killing? How can groups (and individuals) heal from the trauma created by past victimization? How can members of perpetrator and victim groups, or members of groups that have mutually harmed each other, reconcile? What is the role of passive bystanders in allowing violence to unfold, and how can we use the great potential power of “active bystanders” for preventing violence or generating helping?