L.C. Dunn was one of the most significant figures in the emerging field of developmental genetics in the 20th century. His T-locus work with the mouse established a number of important genetic principles, including ideas of gene interaction, the distribution of alleles in wild populations, and the factors that influence fertility. He wrote an important textbook of genetics, Principles of Genetics (1925), in collaboration with Sinnott (and later Dobzhansky); other significant books authored or co-authored by him include Heredity, Race and Society (1946), and A Short History of Genetics (1965). He worked in poultry genetics for eight years at the Agricultural Experiment Station in Storrs, CT, from 1920-1928. The remainder of his career was spent at Columbia University, where he worked with rats, mice, and fruit flies, and proved himself to be an inspiring teacher as well. His interest in international scientific collaboration led him to establish ties to Soviet scientists, and to help relocate refugee scientists during World War II. He remained active in his profession to the end of his life. This collection includes correspondence, reports, notebooks, lectures, and photographs. It is a rich collection, documenting the development of American genetics as well as Dunn's interests in humanitarian efforts and international affairs. There is significant material relating to American-U.S.S.R. contacts, particularly in the files on the American-Soviet Friendship Council and the American-Soviet Science Society. There is much, as well, on the impact of the Lysenko controversy in the U. S. Dunn's interest in European scientists can also be seen in the sizable amount of material on the Emergency Committee in Aid of Displaced German Scholars. Material relating to the Kilgore and Magnusson bills for the support of science (predecessors to the NSF) are also in the collection. Of note are data on the following: National Research Council Committee on Experimental Animals and Plants; research on the population study of the Jewish community in Rome; and Columbia University. There is much in the correspondence concerning Drosophila, poultry genetics, and other such topics; Walter Landauer is Dunn's major correspondent.

The maize geneticist Barbara McClintock (1902-1992) is credited with the discovery of "jumping genes," that is chromosomal "crossing over" and translocation. She received the Nobel Prize in Physiology or Medicine in 1983. The collection is organized into six series: I. Correspondence, 1931-1991; II. Subject files, 1938-1989; III. Works by McClintock, 1944-1989; IV. Works by others, 1927-1991; V. Research notes, notebooks, and card files, 1930s-1990s ; VI. Photographs, 1928-1991.

Mostly concerned with Blakeslee's studies on beans, blood groups, colchicine, Datura, embryo cultures, and horticulture. Many letters relate to the support and direction of the Smith College Genetics Experiment Station, which he headed. Other letters are about the Carnegie Institution of Washington, "Biological Abstracts," American Association for the Advancement of Science, American Philosophical Society, Institut de France, University of Connecticut. Also contains travel letters from Germany and miscellaneous lectures.

A bacteriologist from MIT, Salvador E. Luria's work with Max Delbruck on bacteriophage demonstrated that bacterial resistance to certain phages arose through genetic mutations. His later work showed that phages also mutate genetically. He received the Nobel Prize in Physiology or Medicine in 1969 with Max Delbruck and Alfred D. Hershey. The collection is organized into seven series: I. Correspondence, 1938-1992 ; IIa. Subject Files, 1938-1990 ; IIb. Personal Material. 1923-1991 ; III. Works by Luria, 1938-1987 ; IV. Works by Others, 1944-1990 ; V. Research Notes and Notebooks, 1941-1979 ; VI. Course Material, 1931-1991 ; VII. Photographs and Negatives, 1957-1982. Arrangement: Alphabetical by folder title and then chronological within each folder.

The geneticist Milislav Demerec emigrated from Yugloslavia in 1919, spending nearly his entire career in the Department of Genetics at Cold Spring Harbor Laboratory. Working initially on the genetics of maize and later on Drosophila virilis, his research interests included radiation and chemical mutagenesis, and during the Second World War, penicillin and the genetics of antibiotic resistance. Demerec served as head of the laboratory at Cold Spring Harbor from 1941 until 1960. The Demerec collection contains the extant professional papers of Milislav Demerec, dating primarily from the time of his arrival at Cold Spring Harbor until his retirement. In addition to his correspondence with colleagues, the collection includes interesting material on the administration of Cold Spring Harbor laboratory during the 1940s and 1950s, data and research notes, material relating to professional organizations (e.g. Genetics Society of America, American Society of Naturalists), a lengthy series of lectures given by Demerec, and a large number of photographs pertaining to Demerec's research, but also to his colleagues and Cold Spring Harbor itself. There is also a Register of visitors to the laboratory (1927-1945) and a Milislav Demerec reprint list.

Ernst Wolfgang Caspari was an important contributor to behavior and developmental genetics, working primarily on the mealmoth Ephestia. Trained in Alfred Kuhn's laboratory at the University of Göttingen (1933-1935), Caspari was forced from his position by the Nazis in 1933, escaping to the United States five years later. As a professor of biology at Lafayette College, Wesleyan University, and the University of Rochester, Caspari continued his research on Ephestia, mouse genetics, and behavior genetics until his retirement in 1975. The Caspari Papers includes correspondence, papers, grant reports, and lectures relating to Caspari's genetic research dating primarily from the period after his departure from Germany. In addition to substantial material on behavior genetics and human evolution, the collection includes correspondence relating to Caspari's editorial work for Advances in Genetics, and his involvement with the American Institute of Biological Sciences, the Center for Advanced Study in the Behavioral Sciences, Cold Spring Harbor Laboratory, Fifth Banff Conference on Theoretical Psychology, Genetics Society of America, International Conference on the Unity of Science, Social Science Research Council, Committee on Genetics and Behavior, and the U.S. Atomic Energy Commission.