This volume summarizes and assesses the current state of knowledge about strategies to prevent youth violence. Interpersonal violence consists of a complex variety of life-threatening and lethal behaviors which have in common that they all consist of the infliction of injury upon a person by a person. As is true of most human diseases, violence is also multi-determined; that is, it is a product of the interactions among a variety of biological, psychological, and social variables (including, among the latter, economic, cultural, and historical forces and processes). By focusing on violence committed by and upon youth (adolescents and young adults), we hope in this volume to emphasize the importance of preventive, as opposed to merely retributive, approaches to the problem. Violence is presented as a problem in public health and preventive medicine, rather than as a moral or legal problem and, accordingly, this volume is organized along the classical model in public health, namely, primary, secondary, and tertiary prevention. It should be of interest to researchers and practitioners with a variety of interests and backgrounds, including neuroscientists, pediatricians, psychiatrists, psychologists, health-care specialists, counselors, educators, and others with an interest in interpersonal violence.