Research on the epidemiology of violence has identified two groups of offenders: life-course-persistent offenders and adolescent-limited offenders. The article discusses both groups in detail. In addition, it reviews: predictors of violence as well as protective factors that mediate or moderate the effects of exposure to risk; how violence spreads in adolescence, among adolescence-limited offenders; the foundations of prevention science; effective interventions that reduce known risk factors and enhance protective factors in childhood and adolescence; and the prospects for community-wide violence prevention. Successful intervention programs have offered both home visits (parent training) and center-based educational child care or preschool (aimed at improving cognitive skills). School-based programs for children ages 6 to 12 have effectively prevented adolescent problem behaviors, including violence. Prevention programs aimed at violence in adolescence concentrate on delinquent peer groups, the school setting, and youth gangs. References