Helping vulnerable children develop their full potential is an attractive idea with broad common-sense appeal. However, child well-being is a broad concept, and the legislative mandate for addressing well-being in the context of the current child welfare system is not particularly clear. This volume asserts that finding a place for well-being on the list of outcomes established to manage the child welfare system is not as easy as it first appears. The overall thrust of this argument is that policy should be evidence-based, and the available evidence is a primary focus of the book. Because policymakers have to make decisions that allocate resources, a basic understanding of incidence in the public health tradition is important, as is evidence that speaks to the question of what works clinically. The rest of the book addresses the evidence. Chapter 2 integrates bio-ecological and public health perspectives to give the evidence base coherence. Chapters 3 and 4 combine evidence from the National Child Abuse and Neglect Data System, the Multistate Foster Care Data Archive, and the National Survey of Child and Adolescent Well-Being to offer an unprecedented profile of children as they enter the child welfare system. Chapters 5 and 6 address the broad question of what works. A concluding chapter focuses on policy and future directions, suggesting that children starting out, children starting school, and children starting adolescence are high-risk populations for which explicit strategies have to be formed. This timely volume offers useful insights into the child welfare system and will be of particular interest to policymakers, academics with an interest in Child Welfare Policy, Social Work educators, and Child Advocates. Fred Wulczyn is a research fellow at Chapin Hall Center for Children at the University of Chicago. Richard P. Barth is the Frank A. Daniels Distinguished Professor, School of Social Work, University of North Carolina. Ying-Ying T. Yuan is senior vice president at Walter R. McDonald & Associates, Inc. Brenda Jones Harden is associate professor at the Institute for Child Study at the University of Maryland. John Landsverk is director of the NIMH-funded Child and Adolescent Services Research Center at Children's Hospital, San Diego.