Extensive correspondence of both Horace and Anne Montgomerie Traubel, including letters exchanged between them; diary notes and journals (1873-1917) kept by Horace Traubel, including daily record (1888-1892) of his visits and conversations with Walt Whitman published as With Walt Whitman in Camden (1906); literary files containing prose, poetry, criticism and miscellaneous writings by the Traubels and other authors; correspondence, literary mss., publishing and financial records, proofs, and printed matter comprising the files of The Conservator, a magazine expressing socialist views edited and published by Horace Traubel; personal financial and legal records; and scrapbooks. The collection reflects the Traubels' support of the literary and artistic avant-garde, the arts and crafts and ethical culture movements, and social and political reform. Also includes the papers of their daughter, Gertrude Traubel.

Correspondents include Leonard D. Abbott, Frank Bain, León Bazalgette, Albert Boni, Charles Boni, Richard Maurice Bucke, John Burroughs, Ellen M. O'Conner Calder, Helen Campbell, Edward Carpenter, Charles W. Chesnutt, John H. Clifford, James C. Craven, Homer Davenport, Eugene V. Debs, Theodore Debs, Archie Edington, Elsie Edington, Peter Eglinton, Edgar Fawcett, Charles E. Feinberg, Joseph Fels, Mary Fels, Alexis J. Fournier, Paul Fournier, Clifton Joseph Furness, William F. Gable, Richard Watson Gilder, Charlotte Perkins Gilman, Arthur C. Goodwin, Rosalie Goodyear, Thomas B. Harned, Edmund Marsden Hartley, Herne (Hearn) family, Carrie Rand and George D. Herron, Elbert Hubbard, B. W. Huebsch, Robert G. Ingersoll, William T. Innes, John Johnston, John H. Johnston, David and Rose Karsner, William Sloane Kennedy, Mitchell Kennerly, Courtenay Lemon, Oscar Lion, Daniel Longaker, Julia Marlowe, Laurens Maynard, M. Hawley McLanahan, Lillian and Nathan Mendelssohn, Sidney H. Morse, Thomas B. Mosher, Shigetaka Naganuma, Carleton Eldredge Noyes, Isaac Hull Platt, William M. Salter, Frederic J. Shollar, Charles Sixsmith, Herbert Small, Alfred Stieglitz, Charles Warren Stoddard, James G. P. and Rose Pastor Stokes, James W. Wallace, Samuel Burns Weston, and Gustave Percival Wiksell.