The collection documents Fermi's career as a research physicist and professor in Italy and the United States, including his work with the U. S. Dept. of War, the Atomic Energy Commission, the Office of Naval Research, the American Physical Society, the Institute for Nuclear Studies at the University of Chicago, and the Los Alamos, Bookhaven, and Argonne National Laboratories. It relates primarily to his academic and professional career, and the heaviest concentration of material relates to the years 1939-1954, the period of his residence in the United States. Much of the collection consists of research notes, correspondence, and published and unpublished articles, lectures, books, and courses. Personal materials in the collection include correspondence, identification papers, schoolbooks, engagement calendars, books from Fermi's personal library, financial records, and a large number of awards and memorials. Divisions between series are not strict and the subjects often overlap within series subdivisions. Because many of Fermi's closest friends were also professional colleagues, the classification of "personal" is reserved strictly for materials that are biographical or that contain no recognizably professional content.