The Mark Twain Papers and Project of the Bancroft Library, University of California Berkeley. Archive of Mark Twain's papers and writings Mark Twain Room at Buffalo & Erie County Public Library Samuel Langhorne Clemens collection of papers at New York Public Library Mark Twain Original Manuscripts from 1862–1909 Shapell Manuscript Foundation Mark Twain's Mississippi at Northern Illinois University Libraries Finding aid to the Mark Twain papers at Columbia University. Rare Book & Manuscript Library.