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.

The James V. Neel Papers document nearly every phase of the career of one of the founders of human population genetics in the United States. Neel was particularly thorough and organized, and retained virtually all of his significant scientific correspondence, committee reports, minutes of meetings, and drafts of manuscripts. The collection also includes data collected during Neel's work among the Xavante, Yanomanö and other indigenous populations. In a career that spanned the period from the late work of Thomas Hunt Morgan and Charles B. Davenport to the contemporary world of molecular genetics and nucleic acids, Neel knew, worked with, and corresponded with many of the most influential 20th century practitioners of genetics. The collection begins in earnest in 1943, after Neel had decided to focus on human genetics. Neel's work with Drosophila and none of his Drosophila manuscripts are found in the collection.

One of the seminal figures in the emergence of the Modern or Neo-Darwinian Synthesis during the mid-twentieth century, George Gaylord Simpson (1902-1984) helped define the unique contribution made by vertebrate paleontology to the life sciences. A specialist in Mesozoic and early Cenozoic mammals, Simpson's contributions to the fusion of Darwinian natural selection and Mendelian genetics were both empirical and theoretical, culminating in his major works Tempo and Mode in Evolution and The Meaning of Evolution. From his posts at the American Museum of Natural History (1927-1959), Columbia University (1945-1959), Harvard (1959-1967), and the University of Arizona (1967-1984), Simpson became one of the most influential paleontologists of the century, helped in part by his ability to write successfully for both a technical, professional audience and a popular audience. The Simpson Papers include a comprehensive assemblage of professional and personal correspondence, reflecting nealy all phases of Simpson's career. Written with charm, wit, and a sense of literary style, the correspondence touches on all aspects of modern paleontology, providing an important perspective on the emergence of contemporary evolutionary theory, biogeography, systematic theory and methodology, the relationship of science and religion, and creationism, as well as more general issues in scientific epistemology and social and political issues. The collection also includes autobiographical data and writings, lectures, class notes and papers, research data, material on his scientific expeditions (diaries in carbon form, photos, notes, etc.), publication material (he was author of some 800 publications), extensive photographic material, diplomas, and medals.