Services for families and children are rightfully the focus of intense scrutiny and debate, and there is a clear need to establish a knowledge of which services work well. This volume provides a comprehensive overview of research evidence from the UK and USA on the effectiveness of selected child welfare interventions. It addresses the challenges of measuring effectiveness in child welfare and explains the policy context for child welfare service delivery. Leading international contributors summarize the evidence of effectiveness in each core area, and consider the impact on children's development, parenting capacity and the wider community. Critically, the book also draws out the implications of the evidence for policy, practice and service delivery as well as for future research. This book is essential reading for policy makers, practitioners and commissioners of services in child welfare as well as students and researchers.