Many homicides are committed by young people as part of gang activity, but a considerable number of others are individual actions motivated by rage and jealousy. Gang homicide is primarily an activity of male and minority group members and generally involves juveniles younger than those involved in nongang homicide. Research on violent juvenile offenders describes them as predominantly male minority group members who live in depressed socioeconomic areas. Further, research shows that there is no pattern of progression from nonviolent to violent offenses, that violent juvenile offenders are generally not psychotic or otherwise psychologically disturbed, and that criminal tendencies of peers seem to encourage violent behavior even when there is no gang involvement. Although it is widely believed that violence and other serious juvenile crime is strongly related to illicit drug use, several studies indicate that this belief is not factually accurate, at least in terms of drug use that does not reach the level of addiction. Research supports the opposite possibility, that illicit drug use is the result of an earlier pattern of juvenile delinquency rather than a cause of such delinquency. Historical and theoretical perspectives on juvenile delinquency are detailed, and the development of the juvenile justice system in the United States is reviewed. Consideration is paid to juvenile courts, juvenile detention, institutionalization, juvenile parole, the community as a resource in the treatment of juvenile delinquency, the treatment of juvenile offenders in countries other than the United States, female juvenile delinquency, and the link between media violence and juvenile delinquency. References, notes, tables, figures, and photographs