This report constitutes one of the first activities of the Forum on Adolescence, a cross-cutting activity of the Institute of Medicine and the National Research Council of the National Academies. Established under the auspices of the Board on Children, Youth, and Families, the forum's overaching mission is to synthesize, analyze, and evaluate scientific research on critical national issues that relate to youth and their families, as well as to disseminate research and its policy and programmatic implications. The goals of the forum are (1) review and establish the science base on adolescent health and development and make efforts to foster this development; (2) identify new directions and support for research in this area, approaching research as a resource to be developed cumulatively over time; (3) showcase new research, programs, and policies that have demonstrated promise in improving the health and well-being of adolescents; (4) convene and foster collaborations among individuals who represent diverse viewpoints and backgrounds, with a view to enhancing the quality of leadership in this area; and (5) disseminate research on adolescence and its policy implications to a wide array of audiences, from the scientific community to the lay public.