The information came from a review of research literature and news articles on street and prison gangs; telephone interviews during 1991 with more than 50 gang researchers, criminal and juvenile justice officials, and other researchers and practitioners; public hearings; and a review of program materials and research. The analysis focused on definitions of gangs and gang-related crimes, the characteristics of gangs and their activities, the problems that street gangs create in their communities, program options, and state-of-the-art programming. Programs are described that intervene in the lives of high-risk youth through education, job skills development, and family training and counseling; programs aimed at organizing communities to resist gangs; and law enforcement, prosecution, and corrections strategies to reduce gang- related crime. The discussion also emphasizes the need to develop community-based and multifaceted gang programs that in some cases may change the basic structure of crucial institutions serving communities with gangs. Chapter notes, appended program and research descriptions, and 137 references