Minutes; correspondence; reports; memoranda; grant proposals. Early minutes are of the Joint Committee on the Proposed American Institute of Physics (AIP), February 1931, which was formed at the request of Karl T. Compton of the American Physical Society (APS) and included other members of the APS, the Optical Society of America, and the Acoustical Society of America. Minutes also include those of the Executive Committee (1931-1988), the Governing Board (1931-1988), and joint member society meetings (1936-1988). Correspondence (1931) from the founding committee concerns the establishment of the AIP and election of its first Executive Secretary. Collection also contains reports, correspondence, and minutes of expired AIP committees (1945-1976) pertaining to publishing, policies, finances, and nominations; and grant files (1957-1973) consisting of correspondence, memoranda, proposals, and progress reports relating to inactive grants awarded to the AIP as well as some rejected proposals. Correspondents include: Henry A. Barton, Karl T. Compton, and George B. Pegram. The later addition to the collection includes material on AIP Executive Commitee and Governing Board meetings (1942-1985) and general correspondence (1946-1971). Also includes budgets, financial reports, and annual reports (1936-1971, not inclusive), and files on AIP buildings. Includes some Member Society meeting minutes (American Physical Society, American Association of Physics Teachers, Optical Society of America, Acoustical Society of America, American Astronomical Society, American Vacuum Society, American Association of Physicists in Medicine, and Society of Rheology), and correspondence.