Rosalyn Sussman Yalow (1921-2011) was an American medical physicist. Not believing that any good graduate school would admit and provide financial support to a woman, she took a job as a secretary to Michael Heidelberger, a biochemist at Columbia University's College of Physicians and Surgeons. She graduated from Hunter College in January 1941 and took two tuition-free physics courses under government auspices at New York University. She earned her Ph.D in 1945 at the University of Illinois, where she was the only woman among the department's 400 members. After graduating, Yalow joined the Bronx Veterans Administration Hospital to help set up its radioisotope service. There she collaborated with Solomon Berson to develop radioimmunoassay (RIA) a radioisotope tracing technique that allows the measurement of tiny quantities of various biological substances in human blood as well as a multitude of other aqueous fluids. In 1975 Yalow and Berson (1918-1972) were awarded the AMA Scientific Achievement Award. In 1976 she became the first female recipient of the Albert Lasker Award for Basic Medical Research. In 1977 she received the Nobel Prize, together with Roger Guillemin and Andrew V. Schally for her role in devising the radioimmunoassay (RIA) technique that by measuring substances in the human body, that made possible the screening the blood of donors for such diseases as hepatitis among other uses. She was elected a Fellow of the American Academy of Arts and Sciences in 1978 and received the National Medal of Science in 1988. She died in 2011 at the age of 89.