"This book provides the epidemiological background for a new and important way of thinking about how and when we intervene to reduce health inequalities. Professor Davey Smith's research on the life course and health is truly innovative and unique. Many academics from diverse disciplines will want this as part of their permanent libraries." John Lynch, School of Public Health, University of Michigan "This book will become a classic for those interested in health inequalities." Jenny Roberts, London School of Hygiene and Tropical Medicine