Stafford Leak Warren (July 19, 1896 - July 26, 1981) was an American physician and radiologist who was a pioneer in the field of nuclear medicine and best known for his invention of the mammogram. Warren developed the technique of producing stereoscopic images of the breast with X-rays while working in the Department of Radiology at the University of Rochester School of Medicine. Warren was commissioned as a colonel in the United States Army Medical Corps in 1943 and appointed Chief of the Medical Section of the Manhattan Engineering District. He was responsible for the health and safety of the thousands of personnel involved in the Manhattan Project. He was present at the Trinity nuclear test in Alamogordo, New Mexico where he was responsible for the safety aspects of the detonation of the world's first nuclear weapon. He led a survey team from the Manhattan Project to assess the effects of the atomic bombings of Hiroshima and Nagasaki. In 1946 he was Chief of the Radiological Safety Section of the Joint Task Force for Operation Crossroads, the nuclear test at Bikini Atoll. In 1947 Warren became the first dean of the School of Medicine at the University of California, Los Angeles (UCLA). Under his leadership, the new school grew from nothing to a major medical school. Although controversial and opposed by James Bryant Conant, Warren would speak out about the dangers of nuclear fallout from weapons testing from about 1947 onwards and upon the Castle Bravo test in 1954 his views were lent some credence, which informed opinion leading up to the Partial Nuclear Test Ban Treaty. Warren became Vice Chancellor, Health Services in 1962 at UCLA. From 1963 to 1965 he served as special assistant to President John F. Kennedy and later Lyndon B. Johnson on mental retardation. Returning to UCLA in 1965, he became professor emeritus, a position he held until his death in 1981. In 1971, he was awarded the Enrico Fermi Award for his contributions to science and medicine. Early life Stafford Leak Warren was born in Maxwell, New Mexico on June 19, 1896. He attended the University of California, Berkeley, where he earned his Bachelor of Arts degree in 1918. He married Viola Lockhart on May 22, 1920. Their marriage produced two sons and a daughter. He went to medical school at the University of California, San Francisco, graduating with his Doctor of Medicine degree