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 Valentine-Masters mss., 1915-1944, consists of the correspondence of businessman, bookseller, and collector, John Valentine, 1895-1955, with poet Edgar Lee Masters, 1868-1950.