Professional papers of Bergen Davis, including correspondence, manuscripts, photographs, memorabilia, and printed materials. The correspondence consists chiefly of Davis' typescript carbons of his letters to Columbia colleagues, other physicists, and other individuals at various manufacturers of equipment. The topics covered deal with Columbia students, faculty, course and research work, and his life long interest in the study of x-rays. The cataloged letters include one each from Michael I. Pupin, Isidor I. Rabi, and Robert Simpson Woodward, one lengthy letter from Davis, and ten letters from Nicholas M. Butler. Also included are letters from Davis' wife relating to the research of Lucy J. Hayner and Harold Webb for Webb's biography of Davis that appeared in the National Academy of Sciences' BIOGRAPHICAL MEMOIRS (v. 34, 1960) along with extensive notes, bibliographies and manuscript and typescript versions of Webb's article. There are also manuscripts, typescripts, and notes by Davis relating to his research and writings, photographs of Davis and of his x-ray spectograph, and clippings and memorabilia of his life and work.