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.

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.