This report from the United States Surgeon General is the result of a review of the scientific literature and analyses of new data relating to youth violence. It identifies and quantifies factors, in particular settings of combinations, that increase the probability that violence will occur. It also presents an array of interventions of well-documented effectiveness in helping young people whose lives are already marked by a propensity for violence as well as in preventing others from viewing violence as a solution to needs, wants, or problems. This report is divided into six chapters. The first serves as an introduction and offers chapter conclusions for chapters two through five. Those chapters discuss the magnitude of youth violence; the developmental dynamics of youth violence; risk factors for youth violence; and prevention and intervention. The final chapter examines a vision for the future. Each chapter includes a list of references. The executive summary of this report is included in a separate booklet. (Contains an index.) (MKA)