The review attempts to determine lessons learned from previous attempts at prevention and intervention, what has failed, and what looks promising. The chapter evaluates past youth gang programs and new approaches for preventing and reducing youth gang problems and recommends an intervention and prevention strategy based on the review. The article recommends three strategies: targeting gang problems directly; targeting gang problems within a comprehensive strategy for dealing with serious, violent, and chronic juvenile delinquency; and targeting gang-related (and gang-motivated) homicides. The third program recommendation is based in part on the Epidemiology of Youth Gang Homicides, which the chapter discusses in detail. The program model that proves most effective is likely to contain multiple components, incorporating prevention, social intervention, treatment, suppression, and community mobilization approaches. Gang problem components must be integrated in a collaborative approach with full interagency coordination, supported by a management information system and rigorous program evaluation. Tables, notes