Jeanne Guillemin-Meselson, medical anthropologist and author, died of cancer, aged 76, on November 15 at her home in Cambridge MA, surrounded by her immediate family. She was a graduate of Harvard College, class of 1968, Professor of International Relations and Anthropology at Boston College, where she taught for 33 years, and Senior Fellow in the Security Studies Program at MIT from 1999 until her death. She was loved by generations of undergraduates at BC and by the doctoral candidates she mentored at MIT. Her doctoral dissertation at Brandeis University, “Urban Renegades: The Cultural Strategy of American Indians” (Columbia 1973) documented how a community of Native Americans adjusts to life in an urban environment while retaining much of its traditional culture. In “Mixed Blessings: Intensive care for newborns” (Oxford 1986) she and her co-author Lynda Holmstrom explored the interactions and ethical dilemmas of parents, nurses and physicians in the care of 103 critically premature infants from admission to discharge. In the 1980s Guillemin joined her husband, Harvard biologist Matthew Meselson, in a series of investigations related to allegations of biological warfare and the misuse of biomedical science by government biological weapons programs. Analyzing a large set of interviews with refugees fleeing Laos into Thailand who claimed they had been attacked with “poison from the sky”, the so-called yellow rain”, she found no evidence for the constellation of symptoms cited by the US State Department as evidence for such attacks. This, together with an array of other evidence, made it clear that the yellow material falling from the sky was not a poison, but rather harmless feces from swarms of giant Asian honeybees (Scientific American, September 1985). In 1992, Guillemin, Meselson and a small team of Americans and Russians undertook an independent investigation of an April 1979 outbreak of anthrax in the Soviet city of Sverdlovsk, now Ekaterinburg. The Soviet government claimed the cause was consumption of infected meat. But interviews organized and in most cases conducted by Guillemin with the families and friends of 66 of those who died or fell ill allowed the construction of an epidemiological map showing that nearly all the victims worked or lived in a narrow zone exactly parallel to the wind direction on Monday April 2, 1979, decisively showing that the outbreak was caused by the release of an aerosol of anthrax spores emanating from a military facility in the city, as reported in Science 18 Nov 1984 and described in her book Anthrax: The Investigation of a Deadly Outbreak (California 1999). With a MacArthur Foundation writing award, she next wrote Biological Weapons: From State-sponsored Programs to Contemporary Bioterrorism (Columbia 2005), which provided a concise history of how the US, the Soviet Union and other nations developed anthrax and other microbes as strategic weapons. Renounced by President Richard Nixon in 1969, such weapons are now prohibited by the Biological Weapons Convention of 1972. After the 2001 anthrax letter attacks in the US, Guillemin wrote American Anthrax: Fear, Crime, and the Investigation of the Nation's Deadliest Bioterror Attack (Macmillan/Holt/Times 2011), a detailed account of the attacks and the subsequent FBI investigation. Her most recent book, Hidden Atrocities: Japanese Germ Warfare and American Obstruction of Justice at the Tokyo Trial, (Columbia 2019), nominated for a Pulitzer Prize, describes Imperial Japan's use of biological weapons against China in the 1940s and its horrific experimentation on humans. Based on her extensive archival research, Guillemin found that Washington had ordered the evidence to be concealed from the Tokyo war crimes tribunal to protect the Emperor from defamation and to obtain information from those responsible, none of whom was ever brought to justice, that might be of use in the US biological weapons program. Born in Brooklyn, NY to James Philip and Mary Eileen (Harley) Garrigan, Jeanne moved with her family to Rutherford, New Jersey. Her 1963 marriage to American painter Robert Guillemin ended in divorce. She married Matthew in 1986. As a woman in what was largely a man’s field and for many years a single mother of two sons, she nevertheless rose to distinction in her field. She and Matthew lived in Cambridge Massachusetts and spent summers at Woods Hole, on Cape Cod where Jeanne maintained a lively salon of humanists and scientists. In Cambridge she took great pleasure in meetings with her writing group, a dedicated circle of five talented women writers who met monthly for 30 years. Jeanne and Matthew often visited Paris, where they had many good friends. Her gracious manner and dedication to the life of the mind caused those who knew her to be more humane, more civil, more thoughtful. Mind, heart, and beauty beyond compare. Jeanne is survived by her husband Matthew, her sons Robert (Jeannette) and John Guillemin and stepdaughter Zoe Meselson Forbes (Brian), her grandchildren Claire and Julia Guillemin, and Jake, Sam, and Jesse Forbes and her sisters and brother Patricia, Eileen and Russell Garrigan. This year, Guillemin established an endowment at the MIT Center for International Studies to provide financial support for women pursuing a PhD in international affairs intended to “help women graduate students find new options for special projects that will energize their sense of inquiry and search for knowledge.” Donations may be made at https://giving.mit.edu/jeanne-guillemin or by sending a check made out to “Jeanne Guillemin Endowment” to Center for International Studies, MIT, 1 Amherst Street, E40-435, Cambridge, MA 02139.