The Haldeman mss. II, 1908-1951, consists of correspondence of writers and editors, including Emanuel Haldeman-Julius, 1889-1951, who were connected to Haldeman-Julius Publications.
The Eeden mss. consists of two reels, 1908-1913 and 1914-1918, of negative microfilm of letters and postcards of Upton Beall Sinclair, 1878-1968, novelist, to Frederik Willem van Eeden, 1860-1932, poet and dramatist, from the originals in the Frederik van Eeden-Genootschap at the University of Amsterdam in Amsterdam, Holland.
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 Lewisohn mss., 1922-1937, consist of letters from literary men to Ludwig Lewisohn, 1883-1955, author and critic, and personal letters from Lewisohn to his wife, Mrs. Thelma (Spear) Lewisohn, and her mother, Mrs. Elias Spear.
The Sinclair mss. VI, 1907-1977, consists of correspondence, writings, and miscellaneous papers by and relating to author Upton Beall Sinclair, 1878-1968, his wife Mary Craig (Kimbrough) Sinclair, 1882-1961, and his son David Sinclair, 1901-1987.
The Singer, D. mss., 1948-1965, consist of letters and notes to, from, and about author Upton Beall Sinclair, 1878-1968, collected by educator Donald Lee Singer, 1936-.
The Kus-Nikolajev mss., 1932-1957, are letters from Upton Beall Sinclair, 1878-1968, novelist, to Mirko Kus-Nikolajev, 1896-?, physician of Zagreb, Yugoslavia.