Delinquency prevention programs over the last 20 years have been characterized by disappointment results and 'net widening.' Juvenile delinquency prevention programs reported in other chapters involve intervening with families and in schools to reduce the likelihood of subsequent delinquency. Policy implications are that comprehensive and multileveled interventions are most effective, interventions focusing on the individual should be voluntary, informal relationships may be more influential on high-risk youth than expert help, social agency administrators should be accountable for the context of their services, and extensive social research and intervention experiments should be federally supported. The first principle of delinquency prevention is that it should be primary prevention that focuses on the social and environmental correlates of delinquency; second, prevention efforts that are direct services to families, children, youth, and communities should be structured such that major authority for definition of need and service acceptance rests with the client. Third, a major role of policymakers, researchers, and practitioners ought to be finding 'arrangements to join, not sever, personal troubles and political issues in long-term efforts to reduce human misconduct and misery.' (Rosenheim, 1976). 55 references.