A botanist and historian of science at the University of Pennsylvania, Conway Zirkle published on the history of evolutionary thought and genetics, with a particular interest in the discipline as practiced in the Soviet Union. The Zirkle Papers consist of approximately one linear foot of materials accrued by Zirkle during research for his book on Lysenko-era biology in the Soviet Union, The Death of Science in Russia (1949). Among the miscellaneous materials in the collection are four volumes (0.5 linear feet) of pressed specimens of ferns and algae.

One of the four horsemen of the evolutionary synthesis of the 1940s, Theodosius Dobzhansky played a crucial role in bridging the gap between theoretical and empirical approaches in genetics and in promoting the Neo-Darwinian synthesis. His contributions to the biological species concept and to an understanding the evolutionary dynamics of wild populations of Drosophila were fundamental to the development of modern population genetics and evolutionary thought. The Dobzhansky Papers are a remnant of the correspondence and writings of the geneticist and evolutionary biologist, Theodosius Dobzhansky. The correspondence (7.5 linear feet) provides insight into Dobzhansky's scientific, philosophical, and social views, particularly during the last decade of his life. Equally valuable are the 54 notebooks (ca.1917-1975) which comprise an almost uninterrupted self-commentary on Dobzhansky's career, replete with typescripts of personal letters and short essays sent to colleagues and friends. The collection also contains two unbound volumes of annotated "reminiscences" from the Columbia Oral History Project, 1962; two bound volumes of papers dedicated to him on his 70th birthday; and 1.5 linear feet of photographs.