Recent research on adolescent development has found important behavioral differences between adults and adolescents which have a direct bearing on the design and operation of the justice system. Recognizing the disconnect between juvenile justice policy and emerging findings on adolescent development, the U.S. Justice Department's Office of Juvenile Justice and Delinquency Prevention (OJJDP) asked the National Research Council to convene a committee to conduct a study of juvenile justice reform. The committee's charge was to review recent advances in behavioral and neuroscience research and to draw implications of this knowledge for juvenile justice reform; to assess the new generation of reform activities in the United States; and to assess the performance of OJJDP in fulfilling its statutory mission as well as its potential role in supporting scientifically based reform efforts. In assessing the broad spectrum of research on adolescent development, this committee report notes that "The brain plays an enormous role in determining behavior, but individual development is affected strongly by the interplay between the brain and an adolescent's environment." Environmental influences include interactions with parents, peers, schools, communities, and other factors in youths' social environment. In discussing the implications of this perspective for transforming juvenile justice, this report discusses policy implications for holding adolescents accountable for their offending, the prevention of reoffending, and fairness. This report's recommendations focus on the core components of a sustained process for reforming the Nation's juvenile justice systems based on research findings. OJJDP's role in this effort is discussed. 7 tables and 8 figures