Using data sets consisting of cross-sectional surveys drawn from nationally representative samples of adolescents in the U.S. and official sources of crime statistics, a portrait of aggression and violence among adolescents is presented. Fluctuations in self-reported and official sources of data are examined by year, gender, grade, and race. Both distal and contemporary risk factors for aggression and violence are discussed. Distal risk factors for violence in adolescence are presented using longitudinal studies. The General Aggression Model provides the framework for exploring which contemporary personal and situational factors increase or decrease risk for aggression and violence. Dating aggression in adolescence is placed in the context of normal development and variable according to individual partner and relationship factors. This book presents rigorously tested scientific prevention programs for adolescents with violent and aggressive behavior.