A review of the theoretical perspectives on gangs encompasses sociological and psychological needs met by gangs and how these needs may be met by positive community programs such as sports and recreational programs as well as work experience. Perspectives on gang activity are considered from the viewpoint of gang members, the public, the news media, schools, and police. Descriptions of gang structure and organization focus on specific types of gangs: Hispanic, Asian, black, prison, 'stoner' (white lower- and middle-class gangs usually sharing an interest in heavy metal rock music and sometimes involved in satanism), and car clubs. The relationship of prison gangs to street gangs is also analyzed. A discussion of forms of gang communication covers graffiti, 'street' language, clothing, hand signs, and tattooing. Chapters dealing with possible solutions to the gang problem explain how to measure gang violence, develop and operate a specialized police gang unit, adapt patrol procedures to gang activities, and investigate gang crime. Illustrative photographs and an 8-item bibliography are provided.