Included are the autographs of Robert Browning, Washington Irving, William James, John Stuart Mill, Louis Orléans, comte de Paris, Richelieu, Talleyrand, Alfred Lord Tennyson, Voltaire, John Wesley, and Walt Whitman. There is also personal correspondence addressed to Lewis and his wife, Margaret P. Sherrand Lewis, as well as essays, addresses, and an unpublished novel by Lewis, and a speech on Italian immigrants by Margaret P. Lewis.