This book is the main report of the Office of Juvenile Justice and Delinquency Prevention Study Group on Serious and Violent Juvenile (SVJ) Offenders. It aims to integrate knowledge about risk and protective factors and about the development of juvenile offending careers with knowledge about prevention and intervention programs, including interventions in the juvenile justice system, so conclusions from one area can inform the others. The key questions and issues addressed include: (1) race and ethnicity of SVJ offenders; (2) co-occurrence of SVJ offending and other problems; (3) development of SVJ offending careers; (4) predictors of SVJ offending in adolescence and early adulthood; (5) predictors of youth violence; (6) gangs and SVJ offenders; (7) screening of SVJ offenders; (8) prevention of SVJ offending; (9) community interventions and promising programs to prevent SVJ offending; (10) impact of the justice system on SVJ offenders and prospects for graduated sanctions in a comprehensive strategy; (11) intermediate sanctions and community treatment of SVJ offenders; (12) gaps in knowledge and research priorities; and policy implications. Table