The first chapter introduces the topic of juvenile gangs, as it presents various definitions of gangs and distinguishes among gangs, groups, and subcultures. Three chapters continue the focus on contemporary American gangs with an examination of gang violence, differences among gangs with different ethnic composition, and changes in the nature and extent of female gang behavior over time. These chapters emphasize the variability in juvenile gangs across ethnic and gender boundaries. Two chapters place contemporary American gangs in historical and international perspective, as they trace the history of gang activity in European and American society and examine evidence on the nature and extent of juvenile gang activity in other countries. Three chapters present various approaches to explaining juvenile gang behavior. One chapter discusses typological approaches to crime, delinquency, and gangs; and another chapter reviews theories of juvenile delinquency, crime, and gang behavior up to 1980. A third chapter considers the applicability of contemporary theories of crime and delinquency to the explanation of gang formation, persistence, membership, and gang delinquency. Two chapters review major efforts to combat the influence of gangs and to reduce their illegal behavior. The concluding chapter considers the future of juvenile gangs in the United States in the context of historical and cross-sectional evidence, theory, and experience with intervention programs. 581 references and name and subject indexes