Following an overview of the concept of prevention in the human services, the Federal and State policies governing prevention activities throughout New York States are described. Accordingly, the respective roles of the major State agencies administering programs in the targeted prevention areas are identified. Based on interviews with program directors, some local prevention programs funded under a variety of mechanisms are portrayed. The remainder of the report presents an indepth review of the literature in each prevention area, with attention to the scope of prevention activities, evaluation of the effectiveness of prevention programs, and the theories underlying preventive intervention strategies. Major findings are that preventive activities are not clearly distinguished from treatment activities, and many prevention programs do not base their intervention strategies on causal theories of human behavior. For all prevention areas studied, programs have not adequately evaluated their effectiveness. Results have been discouraging for those programs evaluated with adequate research designs. Appended program descriptions, 17 footnotes, and 130-item bibliography. (Author summary modified)