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.

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.

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.