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.

Britton Chance (1913-2010) was a biochemist and biophysicist as well as a pioneer in the field of biomedical optics. Chance received his Ph.D. in Physical Chemistry from the University of Pennsylvania in 1940 and his Ph.D. in Biology and Physiology from Cambridge University in 1942. Over the course of his nearly eight decade career, Chance was dedicated to the application and transfer of basic scientific research and technology to clinical medicine. The Britton Chance Papers contain correspondence, research notes, experimental data, publication materials, and photographs stemming from Chance's life as a biochemist, biophysicist, and yachtsman. The collection is broken up into fifteen series that document every aspect of his scientific work.

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.

A biochemist at Columbia University, Erwin Chargaff discovered the base-pairing regularities or "complementarity relationships" of nucleic acids that provided one of the key steps in developing a structural model for DNA. During his long career, Chargaff is credited with conclusively falsifying the tetranucleotide hypothesis; demonstrating the existence of a large number of DNA species; and creating the first descriptions of hypochromicity, hyperchromicity, and the denaturation of a DNA. In addition, Chargaff conducted important research on blood coagulation, lipids and lipoproteins, the metabolism of amino acids and inositol, and the biosynthesis of phosphotransferases. He retired to emeritus status in 1974 and remained active in research almost to the time of his death in June 2002. The Chargaff Papers are organized into ten series: I. Correspondence, 1931-1992; Ia. Correspondence, 1949-2002; IIa. Grants, 1930-1982; IIb. Subject Files, 1940-1984; IIc. Subject Files, 1946-2002; III. Works by Chargaff, 1929-1989; IIIa. Works by Chargaff, 1923-2002; IIIb. Reprints, 1977-1999; IV. Works by Others, 1936-1985; IVa. Works by Others, 1976-2002; V. Research Notes and Notebooks, 1929-1951 ; VI. Photographs, 1935-1977; VIa. Photographs, 1928-2002; VII. Audiovisual Materials; VIII. Awards and Certificates, 1958-2001; IX. Lecture Notes, 1942-1985; X. Personal Papers, [1880]-1985.

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.

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.

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.