Jeanne Guillemin, a senior advisor to the MIT Security Studies Program, passed away on November 15, 2019. The author of numerous books and articles, Jeanne was a great scholar, with a ferocious appetite for getting to the bottom of whatever history she chose to study. Her current book, Hidden Atrocities: Japanese Germ Warfare and American Obstruction of Justice at the Tokyo Trial (Columbia University Press, 2017), was nominated for a Pulitzer. Beyond her scholarship, she enlivened the Security Studies Program with both her wit and her charm, while also serving as a role model for our community, especially women scholars. Toward this end, Jeanne recently endowed a fund at the Center for International Studies to support women pursuing PhDs in international affairs at MIT. She will be missed.