Professor of Epidemiology and Nutrition and Chairman of the Department of Nutrition at Harvard School of Public Health and Professor of Medicine at Harvard Medical School. He grew up in Madison, Wisconsin, attended Michigan State University, and graduated from the University of Michigan Medical School before obtaining a Doctorate in Public Health from Harvard School of Public Health. Dr. Willett is a co-investigator of the Nurses' Health Study I, a cohort of over 121,000 female registered nurses 30-55 years of age and he is Principal Investigator of the Nurses' Health Study II, a prospective cohort investigation established in 1989 with over 116,000 female registered nurses. This study is designed to examine the association between lifestyle and nutritional factors and the occurrence of breast cancer and other major illnesses. He has published over 700 articles, primarily on lifestyle risk factors for heart disease and cancer, and has written the textbook, Nutritional Epidemiology. His recent book for the general public, Eat, Drink and Be Healthy: The Harvard Medical School Guide to Healthy Eating has appeared on most major best seller lists.