Contents: Introduction; Part I The Effectiveness of Children's Services: Evidence-based practice in child and adolescent mental health services, Kimberley Hoagwood, Barbara J. Burns, Laurel Kiser, Heather Ringeisen and Sonja K. Schoenwald; Experimentation and social interventions: a forgotten but important history, Ann Oakley; Effect size, practical importance, and social policy for children, Kathleen MacCartney and Robert Rosenthal; Improving outcomes for children in the island of Ireland: the role of philanthropic investment, Michael Little and Ali Abunimah; A place of value for applied and policy studies, Edward Zigler. Part II The Relationship Between Need and Services: Use, persistence, and intensity: patterns of care for children's mental health across 1 year, Elizabeth M.Z. Farmer, Dalene K. Stangl, Barbara J. Burns, E. Jane Costello and Adrian Angold; Youth justice? The impact of system contact on patterns of desistance from offending, Lesley McAra and Susan McVie; Fast track randomized controlled trial to prevent externalizing psychiatric disorders: findings from grades 3 to 9, Karen L. Bierman, John D. Coie, Kenneth A. Dodge, E. Michael Foster, Mark T. Greenberg, John E. Lochman, Robert J. McMahon and Ellen E. Pinderhughes. Part III The Effectiveness of Public Health and Universal Programmes: Is Sure Start an effective preventive intervention?, Michael Rutter; Parenting intervention in Sure Start services for children at risk of developing conduct disorder: pragmatic randomised controlled trial, Judy Hutchings, Tracey Bywater, Dave Daley, Frances Gardner, Chris Whitaker, Karen Jones, Catrin Eames and Rhiannon T. Edwards; Efficacy of the Incredible Years basic parent training programme as an early intervention for children with conduct problems and ADHD, K. Jones, D. Daley, J. Hutchings, T. Bywater and C. Eames; The health and welfare effects of day-care: a systematic review of randomised controlled trials, B. Zoritch, I. Roberts and A. Oakley; Is home visi