Dr. Harold Stewart became Chief of the Laboratory of Pathology, National Cancer Institute, in 1939, and was appointed chief of the Pathological Anatomy Department, National Institutes of Health, in 1954. He retired from NIH in 1969. Along with his longtime colleague Dr. Thelma Dunn, pioneered methods to induce cancer of the stomach and intestines in experimental animals.

Correspondence, reports, minutes, reprints documenting Dr. Shear's professional activities with the National Cancer Institute, including interaction with the International Union Against Cancer and the American Association for Cancer Research.

Correspondence, reprints, drafts, statistical data, reports, and testimony document Nathan Mantel's career as a medical statistician with the National Cancer Institute, George Washington University, American University, and freelance consultant.

The collection documents the varied research and policy-making career of this environmental health specialist with the U.S. Department of Heath, Education and Welfare and the Public Health Service. His papers contain a wealth of primary source research materials and scientific data related to: environmental and industrial hygiene; radon activity; use of beryllium as a rocket propellant; uranium mining; and toxicological, biological and chemical weapon systems.