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.

NIH microbiologist and bacteriologist, Stewart was known for her discovery that certain virus strains can jump species and produce cancers in other hosts. Collection consists of biographical data, correspondence, clippings, reprints, oral history memoir, and laboratory notes.