Correspondence, reports, minutes, and subject files. Correspondence (1931-1964), comprising the majority of this collection, concerns Barton's professional activities, interests, and responsibilities in those positions. Topics of the correspondence include member societies of AIP (American Association of Physics Teachers, American Physical Society, Acoustical Society of America, Optical Society of America, and Society of Rheology), affiliated societies, AIP Corporate Associates, AIP committees, the AIP Governing Board and its Executive Committee, grant proposals, publishing of physics journals, Lancaster Press (AIP printer), the U.S. Navy Department, the U.S. War Department, AIP awards, physics education, selective service, the Scientific Manpower Commission, and the censorship of publications related to nuclear fission during World War II. Also includes an undated audio tape, probably by Barton, reviewing the founding of AIP and its history. Administrative reports and minutes are of the AIP Governing Board and its Executive Committee, the AIP Publications Board, and AIP member societies. Correspondents include: George W. Bailey, Hans A. Bethe, Vannevar Bush, Karl T. Compton, Edward U. Condon, Karl K. Darrow, Homer L. Dodge, Paul D. Foote, R. Clifton Gibbs, Arthur C. Hardy, Ross G. Harrison, Gaylord Harnwell, Elmer Hutchisson, William C. Kelly, Paul E. Klopsteg, Herbert R. Lang, Claude J. Lapp, Walter C. Michels, Joseph C. Morris, Cleveland Norcross, J. Robert Oppenheimer, Thomas H. Osgood, George B. Pegram, Shirley L. Quimby, Floyd K. Richtmyer, Duane Roller, Francis W. Sears, John T. Tate, Merriam H. Trytten, Wallace Waterfall, and Eugene P. Wigner.