Violence is logical to perpetrators, but senseless to outsiders. Most enjoy their violent acts. Based on in-depth interviews with violent persons, this book answers the question, "Why do they do it?" and draws lessons for prevention from what perpetrators themselves say. The four sections of the book covers what violence means to perpetrators, the development of violent behaviors, accountability, and prevention. Violence prevention requires the promotion of trusting relationships, prosocial means of self-regulation, and prosocial beliefs such as promoting the best interests of others.