The manuscripts of father William Mitchell and daughter Maria Mitchell are not easily separated, and are treated here together. The collection includes William Mitchell's autobiography, his memoir of Judge Walter Folger of Nantucket, astronomical and meteorological observations, lectures, family and other correspondence.

This is a diverse collection, including correspondence, drafts of letters, notes and notebooks (on biometric methods; tables and formulae; science, nature and method; coefficient and correlation; vitalism; Japanese language); commonplace book (1924); autobiography; and over one hundred folders of unpublished writings. The correspondence and other material covers a variety of topics, including biology, eugenics, evolution and natural selection, human heredity, paramecia, protozoa genetics, U.S. immigration policy. There is much on the Seventh International Congress of Zoology (1907); letters to his father and wives, and from students and colleagues on his seventy-fifth birthday, 1943 (1 v.); diplomas and certificates of membership; and photographs.

Edward Uhler Condon was a theoretical physicist at Princeton University and Westinghouse Laboratories who later served as director of the National Bureau of Standards (1945-1951), and as the director of research and development (1951-1954) and consulting physicist (1954-1974) at Corning Glass Works. The Condon Papers includes correspondence, notebooks, writings, photographs, and other materials concerning Condon's education, teaching, and his government, industrial, and academic.

Alfred Irving ("Pete") Hallowell was an anthropologist best known for his studies of Ojibwa culture and world-view, and the innovative use of the Rorschach Test in his studies of the psychological interrelations of individuals and their culture. Early in his career, Hallowell worked as a social case worker for Family Service, and even after moving on to study anthropology in 1920 (M.A.), he carried with him an interest in ethnic and racial culture, developing additional interests in psychological testing. Except for the years 1944-1947, when he taught at Northwestern University, Hallowell spent his entire career at the University of Pennsylvania where he was professor of anthropology, professor of anthropological psychiatry in the Medical School, and curator of social anthropology at the University Museum. A cultural anthropologist, Hallowell's use of clinical psychological methods, especially Rorschach tests, was both innovative and controversial in his discipline. In his research, he concentrated on the Algonkian Indians, especially the Abenaki and Ojibwa Indians of Canada and Wisconsin (Berens River, Lake Winnipeg, Manitoba, and Lac du Flambeau, Wisconsin areas), and the Saulteaux of Berens River. The Alfred Irving Hallowell Papers (1892-1981) contain correspondence, subject files, manuscripts of published and unpublished works by Hallowell, papers by colleagues and students, research notes kept by Hallowell, with a special emphasis on social organization, personality, behavior, psychology, religion, and folklore. The collection of several hundred photographs provides rich graphic documentation of Hallowell's work among the Ojibwa and Abnaki Indians during the 1930s.