Letters and carbon copies of letters from Taylor to friends, parishioners, social workers, committee members, unions, editors, officials, politicians, and other associates. Prominent addressees include Jane Addams, Edward Price Bell, Charles R. Crane, Clarence Darrow, Charles H. Dennis, John Palmer Gavit, William Rainey Harper, Julia C. Lathrop, Victor F. Lawson, members of the McCormick family (mostly Katharine D. [Mrs. Stanley] McCormick), Frank McCulloch, Ben Reitman, Raymond and Margaret Robins, Edward L. Ryerson, and associates from the Chicago Theological Seminary, Chicago Commons, the Survey, and the University of Chicago. Some correspondence reflects Taylor's activities at his previous parishes in Hopewell, New York (1873-1880) and Hartford, Connecticut (1880-1892). Much correspondence concerns the daily workings and fundraising efforts of the Chicago Commons and Taylor's many social reform projects. Other letters, particularly those to Sophonisba P. Breckenridge, address the incorporation of the Chicago School of Civics and Philanthropy into the University of Chicago against Taylor's wishes.

See also correspondence in Series 7 (Chicago Commons), Series 8 (Chicago School of Civics and Philanthropy), and Series 9 (Chicago Theological Seminary).