The past decade has seen a growth in research into the social determinants of health. This research challenges the assumptions that investments in the health system and lifestyle behaviours are responsible for health gains. By focusing on inequalities in health, the research has shed light on a range of factors that influence health. This book covers the differential health impacts of family and early development, changes in work and work conditions, health systems, the physical environment of cities, indigenous peoples, rural populations, social capital, culture, and global economic and environmental changes. It contains material that explains how inequality gets 'under the skin', through describing the physiological changes that follow from stress and behaviours. Particularly important is the 'natural experiment' represented by the different political and economic paths taken by Australia and New Zealand over the past two decades and the opportunity this provides to assess the impact on health.