We propose to create the Center for the Prevention of Multiple Problems in Early Adolescence. A center on early adolescent prevention is needed because early adolescence is the period in which the most common and serious problems of adolescence begin and a comprehensive theoretical and practical approach to reducing the prevalence of multiple problems in early adolescence is lacking. The Center will bring together scientists from five organizations, Oregon Research Institute, the Center for Families and Children and the Institute on Violence and Destructive Behavior at the University of Oregon, Oregon Social Learning Center, and Paxis Institute. We request funds for a P30 Center grant, which would create three Cores to integrate and support as many as 15 research projects. These basic and applied projects span the range of research problems needed to prove prevention for early adolescence, including family, school, peer, neighborhood and community influences on substance use, antisocial behavior, depression, and high risk sexual behavior. They include search on the dissemination of empirically supported practices and work developing, refining, and comparing statistical techniques for the analysis of complex, multi-level data sets. The Administrative Core is designed to facilitate integration and synergy through formal and informal mechanisms. A Committee on Theory Development will attempt to articulate a comprehensive theory of the influences on early adolescent development that can guide further research. A Committee on Research Development will define the highest priority research projects to be developed by the Center. The Methodology Core will identify important methodological problems, articulate solutions to them, and train Center staff in implementing them. It will conduct analyses of subgroup effects of interventions and of the influence of fidelity and adherence on outcome and will test the replicability of models of development across project data sets. The Dissemination Core will make the results of Center research available to the scientific community and policy makers and practitioners. But it will also play a leadership role in helping Oregon policy makers and practitioners identify and disseminate empirically supported practices. The Center will enhance the productivity of participating projects by improving their theory, measurement, and analysis. And, it will define the direction of research and practice on early adolescence.