Ichiro Kawachi, MD, PhD, is Professor of Social Epidemiology and Director of the Harvard Center for Society and Health, Harvard School of Public Health. Kawachi's research has focused on uncovering the social, economic, and other group-level determinants of population health. He is the co-editor (with Lisa Berkman) of the first textbook on Social Epidemiology (Oxford University Press, 2000), as well as The Health of Nations (The New Press, 2002) and Neighborhoods and Health (Oxford University Press, 2003).