This series largely consists of Gilman's incoming letters. There are some drafts of outgoing letters. The majority of the letters relate to the Johns Hopkins University. Principal correspondnets include: Andrew Dickson White, Charles W. Eliot, Herbert Baxter Adams, Chrles S. Peirce, William K. Brooks, Ira Remsen, Sidney Lanier, Simon Newcomb, Richard T. Ely, Basil L. Gildersleeve, J.J. Sylvester, Henry Rowland, and Francis Lieber. Other correspondents represented by a lesser volume include a number of notables of the time including Ralph Waldo Emerson, James Russell Lowell, Henry James, Matthew Arnold, Oliver Wendell Holmes, William Cullen Bryant, William Dean Howells, Henry Wadsworth Longfellow, Robert Louis Stevenson, James Garfield, Grover Cleveland, Rutherford B. Hayes, Theodore Roosevelt, William Howard Taft, Woodrow Wilson, Henry Adams, John Hay, William James, George Bancroft, John Dewey, Alexander Graham Bell, Thomas Huxley, Andrew Carnegie, Horace Greeley, Henry Ward Beecher, Helen Keller, and Louis Pasteur. Correspondence not included in this series are letters in Gilman's autograph collection. These are personal letters written to Gilman which he mounted in albums. When these letters were restored, they were assigned to Series 4. A list of these letters is in the container list for Series 4. Letters written by Gilman to his family can be found in Series 10, Series 13, and Series 14.