Most interventions for at-risk youth are group based. Yet, emerging research indicates that young people often learn to become deviant by interacting with deviant peers. In this important volume, leading intervention and prevention experts from psychology, education, criminology, and related fields analyze how, and to what extent, programs that aggregate deviant youth actually promote problem behavior. A wealth of evidence is reviewed on deviant peer influences in such settings as therapy groups, alternative schools, boot camps, group homes, and juvenile justice facilities. Concrete recommendations are offered for improving existing services, and promising alternative approaches are explored. This book is arranged into three parts. Part I, Introduction, contains the first five chapters: (1) The Problem of Deviant Peer Influences in Intervention Programs (Kenneth A. Dodge, Jennifer E. Lansford, and Thomas J. Dishion); (2) Deviant Peer Influence in Interventions and Programs: An Ecological Framework for Understanding Influence Mechanisms (Thomas J. Dishion and Kenneth A. Dodge); (3) Deviant Peer Effects: Perspectives of an Epidemiologist (James C. Anthony); (4) Assigning Youths to Minimize Total Harm (Philip J. Cook and Jens Ludwig); and (5) Is Deviant Peer Influence a Problem, and What Can Be Done?: Qualitative Perspectives from Four Focus Groups (Jennifer E. Lansford and Joel Rosch). Part II, Reviews of Peer Effects, contains the next group of chapters: (6) Deviant Peer-Group Effects in Youth Mental Health Interventions (Kenneth A. Dodge and Michelle R. Sherrill); (7) Deviant Peer Effects in Education (Wendy M. Reinke and Hill M. Walker); (8) Peer Effects in Juvenile Justice (D. Wayne Osgood and Laine O'Neill Briddell); (9) The Effects of Community-Based Group Treatment for Delinquency: A Meta-Analytic Search for Cross-Study Generalizations (Mark W. Lipsey); (10) Peer Effects in Neighborhoods and Housing (Jacob Vigdor); (11) Iatrogenic Outcomes of the Child Welfare System: Vulnerable Adolescents, Peer Influences, and Instability in Foster Care Arrangements (Melvin N. Wilson and LaKeesha N. Woods); (12) Peer Effects in Community Programs, (Jennifer E. Lansford); and (13) Peer Effects in Naturally Occurring Groups: The Case of Street Gangs (Malcolm W. Klein). Part III, Promising Solutions and Recommendations, contains the final chapters: (14) Research-Based Prevention Programs and Practices for Delivery in Schools That Decrease the Risk of Deviant Peer Influence (Rebecca B. Silver and J. Mark Eddy); (15) Promising Solutions in Juvenile Justice (Peter Greenwood); (16) The Important Role of Adults in Children's Lives: Prevention Approaches to Improve Child and Adolescent Behavior and Reduce Deviant Peer Influence (Emilie Phillips Smith, Jean Dumas, and Ron Prinz); (17) Promising Solutions in Housing and the Community (Jens Ludwig and Greg Duncan); (18) Creating a Legal and Organizational Context for Reducing Peer Influence (Joel Rosch and Cindy Lederman); (19) A Functional Contextualist Framework for Affecting Peer Influence Practices (Anthony Biglan, Jeffrey Sprague, and Kevin J. Moore); and (20) Findings and Recommendations: A Blueprint to Minimize Deviant Peer Influence in Youth Interventions and Programs (Thomas J. Dishion, Kenneth A. Dodge, and Jennifer E. Lansford.) [This book was published by Guilford Publications.]