This book draws on findings from psychology, neurology, and genetics, to offer a multi-dimensional analysis of criminal behavior. It explores the biological bases of emotions such as aggression, anger, and hostility and how they– combined with social psychological influences, such as family history and environmental conditions– may lead to violence. Specific case studies, including serial killings, mass murders, family violence, cannibalism, and hitmen, are referenced throughout, providing real-world examples of these theories in action. Issues of free will and the law are discussed as well as suggestions for curbing violent behavior.