The principal letters in this collection are to Otto L. Mohr and concern problems and progress in genetics, the Nobel Prize, and some account of Mohr and his family under the Nazi occupation of Norway, 1940-1945. Included with this group is a partial biographical essay on Calvin Blackman Bridges.

Working on bacterial viruses in 1945, Seymour S. Cohen offered the first systematic exploration of the biochemistry of virus-infected cells and of how viruses multiply. His subsequent research included delineating the phenomenon of thymineless death, developing derivatives of ara-A compound, working on RNA synthesis, studying the effects of polyamines on metabolic systems, and studying plant viruses (including viral cations). Much of his research has contributed to the chemical treatment of cancer and viral infections.

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.

The correspondence in this collection concerns behavior genetics, evolution, heredity, etc. There is material relating to the congresses of the Permanent International Committee on Genetics, and the IXth (Bellagio, 1953), Xth (Montreal, 1958), and XIth (The Hague, 1963) International Congress of Genetics. There is also correspondence pertaining to the Cold Spring Harbor Symposium on Quantitative Biology (1955), the Mendel Semi-Centennial Symposium (1950), the Soviet geneticists' visit to the U.S. in 1967, and to Anton R. Zhebrak.

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.

Between 1968 and 1978, the historian of science Horace Freeland Judson conducted extensive oral history interviews with biochemists and molecular biologists relating to the development of their field. The correspondence, transcripts of interviews, and taped interviews that comprise the Judson collection formed the research material used by Judson in his book, The Eighth Day of Creation (New York, 1979). Permission to quote must be obtained from Dr. Judson and access to some files is restricted.