The report explores the research on topics such as definitions of youth gangs and related terms; the nature and causes of the gang phenomenon; and the effectiveness of various responses from law enforcement, the judicial system, social welfare agencies, schools, and communities. The analysis concludes that a comprehensive policy is needed, under the sponsorship of some authoritative agency and involving cooperation between public and voluntary agencies and community groups. This policy should be developed and systematically tested, particularly in cities where the youth gang problem is chronic, serious, and entrenched. An early intervention approach based in the public schools, in collaboration with community-based youth agencies, the police, and community groups should also be tested, particularly in cities or neighborhoods with emerging gang problems. 368 references