Biography of Barbara McClintock America's most distinguished cytogeneticist, Barbara McClintock, was born in Hartford, Connecticut on June 16, 1902. After attending high school in New York City, she enrolled at Cornell University in 1919 and from this institution received the B.S. degree in 1923, the M.A. in 1925, and the Ph.D. in 1927. She served as a graduate assistant in the Department of Botany from 1924-27 and in 1927, following completion of her graduate studies, was appointed an Instructor, a post she held until 1931. Dr. McClintock was awarded a National Research Council fellowship in 1931 and spent two years as a fellow at the California Institute of Technology. In 1933 she received a Guggenheim Fellow- ship which enabled her to spend a year abroad at Freiburg. She returned to the States and to the Department of Plant Breeding at Cornell in 1934. She left Cornell in 1936 to accept an Assistant Professorship in the Department of Botany at the University of Missouri. In 1941 she joined the staff of the Carnegie Institution of Washington, and began a happy and fruitful association which has continued to the present time. She was a Staff Member of the o Carnegie's Genetics Research Unit at Cold Spring Harbor, Long Island, New York until 1967 when she was made a Distinguished Service Member, a rank which she presently holds. McClintock was appointed Andrew D. White professor-at-large at Cornell in 1965, a fitting recognition by her Alma Mater of the great distinction she has achieved as a scientist and scholar. Barbara McClintock was awarded the honorary Doctor of Science degree by the University of Rochester in 1947, by Western College in 1949, by Smith College in 1958, by the University of Missouri in 1968, by Williams College in 1972, by Harvard University in 1979, and by Rockefeller University in 1980. She was the recipient in 1947 of the Achievement Award of the American Association of University Women, was given the Award of Merit by the Botanical Society of America in 1957 and in 1967 was selected by the National Academy of Sciences for the Kimber Award in Genetics. She received the National Medal of Science in 1970, the Lewis S. Rosenstiel Award in 1978, a Salutation by the Genetics Society in 1980, the Thomas Hunt Morgan Medal by the Genetics Society in 1981, the Wolf Prize in Medicine in 1981, the Lasker Basic Medical Research Award in 1981, and was made a MacArthur Foundation Prize Fellow Laureate in 1981. McClintock is a member of the National Academy of Sciences, the American Philosophical Society, and the American Academy of Arts and Sciences, She was elected Vice President of the Genetics Society of America in 1939 and President in 1945. As Special Consultant to the Rockefeller Foundation she has in recent years been instrumental in advancing the training of geneticists in several Latin American countries.