The Kimbrough mss., 1961-1967, consists of the correspondence of bond salesman Hunter Southworth Kimbrough, 1900-1994, concerning his relationship with his brother-in-law, Upton Beall Sinclair, 1878-1968.
The Lesser mss., 1933-1971, consist chiefly of the correspondence between Sol Lesser, 1890-1980, motion picture executive, and Upton Beall Sinclair, 1878-1968, novelist, and others concerned with their interests.
The Lush mss., 1956-1957, consists of two letters from Upton Beall Sinclair, 1878-1968, author, and a letter from Mrs. Mary Craig (Kimbrough) Sinclair, (Mrs. Upton Beall Sinclair), 1883-1961, author, to Samuel Beryl Lush, 1893?-?, cotton merchant.
The DeWitt mss., 1941-1955, consists of letters from Upton Sinclair, 1878-1968, author, to Samuel Aaron DeWitt, 1891-1963, poet and businessman, and correspondence between Mary Craig (Kimbrough) Sinclair, (Mrs. Upton Sinclair), 1883-1961, and DeWitt.
The Sinclair mss. IV, 1900-1963, consists of correspondence, writings, and monetary statements of author Upton Beall Sinclair, 1878-1968, and of his wife, Mary Craig (Kimbrough) Sinclair, 1883-1961.
