The Clark mss., 1909-1957, consists of the letters and writings of author, editor, and publisher Thomas Curtis Clark, 1877-1953, as well as the autographs and poems of other writers collected by him.
The Ehrmann mss., 1899-1926, consists of letters to Max Ehrmann, 1872-1945, author, from Eugene Victor Debs, Frank Harris and Upton Beall Sinclair, and Mrs. A. Schember.
The Appleton-Century mss., 1846-1962, consists of the office files of the publishing company, its two predecessors, D. Appleton & Co., and the Century Co., and to a small extent its successor, Appleton-Century Crofts, Inc.