The Curry mss., 1919-1945, primarily consists of the letters of socialist leader Eugene Victor Debs, 1855-1926 to his secretary Mabel (Dunlap) Curry, 1868-1947.
The Hapgood, M.D., mss., 1912-1975, consists of the correspondence and writings of Socialist leaders Mary Donovan Hapgood, 1886-1973, and Powers Hapgood, 1899-1949.
The Walker mss., 1912-1920, consists of the correspondence of socialist leader Eugene Victor Debs, 1855-1926, to cartoonist Ryan Walker, 1870-1932, and author Mrs. Maud Helena (Davis) Walker, (Mrs. Ryan Walker), 1870-1925.
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.