Correspondence, diaries, laboratory notebooks, subject files, drafts and copies of speeches, articles and books, newspaper clippings, printed material, and other papers, chiefly of Bell, but also of various members of the Bell, Hubbard, Fairchild, and Grosvenor families. Papers of Bell's father-in-law, Gardiner Greene Hubbard, include material on the founding of Bell Telephone company and National Geographic Society. Much of the material relates to Bell's invention of the telephone (1876). Other material relates to his interests in the education of the deaf, eugenics, marine engineering, and aviation. Correspondents include Samuel L. Clemens, Sarah Fuller, Edward M. Gallaudet, Joseph Henry, Helen Keller, George Kennan, Samuel P. Langley, Sinclair Lewis, Guglielmo Marconi, Simon Newcomb, Benjamin Pierce, John Wesley Powell, and Charles Sumner Tainter.