The third volume of "The Future of Children" examines the causes and consequences of increasing rates of obesity and overweight among children. It also reviews specific policies and programs aimed at reducing obesity and overweight and the related health problems that result. Contents include: (1) Introducing the Issue (Christina Paxson, Elisabeth Donahue, C. Tracy Orleans, and Jeanne Ann Grisso); (2) Childhood Obesity: Trends and Potential Causes (Patricia M. Anderson and Kristin F. Butcher); (3) The Consequences of Childhood Overweight and Obesity (Stephen R. Daniels); (4) Markets and Childhood Obesity Policy (John Cawley); (5) The Role of Built Environments in Physical Activity, Eating, and Obesity in Childhood (James F. Sallis and Karen Glanz); (6) The Role of Schools in Obesity Prevention (Mary Story, Karen Kaphingst, and Simone French); (7) The Role of Child Care Settings in Obesity Prevention (Mary Story, Karen Kaphingst, and Simone French); (8) The Role of Parents in Preventing Childhood Obesity (Ana C. Lindsay, Juhee Kim, Steven Gortmaker, and Katarina M. Sussner); (9) Targeting Interventions for Ethnic Minority and Low-Income Populations (Shiriki Kumanyika and Sonya Grier); and (10) Treating Childhood Obesity and Associated Medical Conditions (Sonia Caprio).