Nancy H. Ruddle, Professor Emerita of Epidemiology (Microbial Diseases) and senior research scientist, served on the Yale faculty from 1975 to 2016. She received her Ph.D. from Yale and was an associate research scientist in the Department of Surgery, a lecturer in microbiology, and a postdoc in microbiology. She was appointed assistant professor of microbiology in the Department of Epidemiology and Public Health, now known as the Yale School of Public Health, and rose through the ranks to professor. She maintained a joint appointment in the Department of Immunobiology at Yale School of Medicine from 1991 to 2016 and was awarded the John Rodman Paul Chair in 2002. In the course of her career, she served as head of the Division of Microbial Diseases in the School of Public Health, director of graduate studies, and acting associate dean and chair on two separate occasions. She is a fellow of the American Association for the Advancement of Science and the Connecticut Academy of Scientists and Engineers. Ruddle is known for her discovery of lymphotoxin and its roles in autoimmunity and development and her elucidation of organized lymphoid accumulations, called tertiary lymphoid organs.