The A. W. Kopp autograph collection contains three books of autographs and various loose autographs. One book is dated 1909 to 1910 and contains an autograph of Gustav Mahler and Sergei Rachmaninoff (with an accompanying musical quote), one is dated 1914 to 1917 and contains an autograph of U.S. President Theodore Roosevelt, and one is dated 1917 to 1921 and contains an autograph of Harry Houdini, Edgar Lee Hay, and Marjory Stoneman Douglas. Among the loose autographs, there are ones of Daniel Webster and Oliver Wendell Holmes. Also included are a book of receipts from New York dated 1784 to 1786, a book of poetry from residents of Danzig dated 1833 to 1853.