Some groups of people are healthier than others. Overwhelmingly, for almost all kinds of morbidity and mortality, groups at the bottom of the social scale are less healthy than those at the top. But this simple observation describes a complex phenomenon that has become a major focus of research, teaching, intervention, and public policy and has led to recognition of the stark power of social determinants of population health. Why are poorer, less educated, lower-class groups less healthy than others? Historically, and indeed today, this has been a question that has polarized researchers, policy-makers, politicians, and casual onlookers. The debate is intensely contentious because if health inequalities are largely a consequence of people at the bottom of the social scale lacking resources and living in poor conditions, then, arguably, policies must be directed towards correcting those material deficits. But if inequalities in health are largely due to the social inequalities among people and their feelings about their position in relation to other people, then policies that encourage a more egalitarian society may be needed to close the health gap. Edited by two leading scholars in the field, the four volumes in this new Routledge Major Work bring together key research from a wide range of disciplines, including epidemiology and public health, sociology, psychology, biology, and public policy, to provide a coherent and multidisciplinary synthesis of this vast and vibrant literature. Volume I assembles the basic evidence of health inequalities in different countries and different time periods, and focuses on the extent to which health inequalities result from social selection versus social causation. Volume II covers the main schools of thought on the causes of health inequalities and the pathways linking low social status to poor health. The focus of the third volume is on the effectiveness of interventions that have been designed to reduce health inequalities. The theme of Volume IV is the social and political ecology of health and the biology and psychology of human sensitivity to the social environment. Fully indexed and with a comprehensive introduction newly written by the editors, which places the collected material in its historical and intellectual context, Health and Inequality is an essential work of reference for both scholars and practitioners hoping to understand (and mitigate or remove) inequalities in health.