The papers of Joseph Pulitzer (1885-1955) span the years 1897-1958, with the bulk of the material dated between 1925 and 1955. The collection consists of family and general correspondence, subject and business files, and personal financial records relating primarily to Pulitzer's editorship of the St. Louis Post-Dispatch. Subjects include the operation and production of the newspaper, its working philosophy, internal business management, and editorial policies. The collection is organized into five series: Family Correspondence, General Correspondence, Business File, Subject File, and Financial Papers.

The Family Correspondence features Pulitzer's letters to his children, Joseph (1913-1993), Michael, Elinor, and Kate Davis. His sons followed him to St. Mark's School in Southborough, Massachusetts, and he maintained close interest in their educational, habits, extracurricular activities, and the character of their friends. Equal concern is shown in his letters to his daughters, Elinor at Stuart School of Art in Boston, and Kate Davis at Foxcroft School in Middleburg, Virginia. The correspondence continues throughout the adult lives of his children. This series also contains a large number of letters pertaining to the settlement of the estate of his father, Joseph Pulitzer (1847-1911).

The General Correspondence series contains letters between Pulitzer and leaders in government and journalism. Many are of a routine nature, but those of interest, such as with Pulitzer's friend, Bernard M. Baruch, discuss divergent topics on national and international affairs, business trends, and hunting and fishing. Correspondence with publishers includes Arthur Hays Sulzberger, Adolph S. Ochs, Agnes Elizabeth Ernst Meyer, Eugene Meyer, Joseph Medill Patterson, and Norman Chandler. This group of papers also contains letters from Sumner Welles, Herbert Bayard Swope, and Stuart Symington, among others.

The Business File focuses on the attention Pulitzer bestowed on all phases of his newspaper's production. Memoranda to staff of the St. Louis Post-Dispatch range from discussion of editorial policy to Pulitzer's objection to the tone of voice used by a secretary. Topics in the editorial files treat the range of domestic and foreign problems covered by his newspapers.

Although Pulitzer was absent from the Post Dispatch offices for considerable periods of time on fishing and hunting trips, he maintained contact and control of the newspaper through telegrams and memoranda. Included are communications with editorial writers and Washington bureau reporters such as Oliver Kirby Bovard, Irving Dilliard, Benjamin Harrison Reese, Raymond L. Crowley, Charles G. Ross, Raymond P. Brandt, Paul Y. Anderson, and Marquis W. Childs. Subjects cover the spectrum of newspaper operations and include contract negotiations with the American Newspaper Guild and other unions involved in the publication of the Post-Dispatch , Pulitzer's policy of refusing to accept advertising he considered fraudulent, his analyses of the cost factors in the management of the paper, and comparisons of the operation of the Post-Dispatch and competitive newspapers.

The Business File also includes information on special issues Pulitzer pursued, such as his opposition to President Franklin D. Roosevelt's court-packing plan in 1937, the symposium he organized during World War II on the subject “What We Are Fighting For,” and the series of articles he wrote during an inspection of Nazi concentration camps. The papers also reveal the pride Pulitzer took in the visual aspect of his newspaper, his attention to the appropriateness of typefaces, and his use of advanced rotogravure processes at the Post-Dispatch .

The Subject File contains papers concerning the Pulitzer Prizes instituted by his father, including records relating to nominations, meetings of the advisory board, and the presentation of the awards. Treated also are the management of Pulitzer's principal residence at Clayton, Missouri, and his summer home at Bar Harbor, Maine. There are extensive files on hunting and fishing, replete with records of his catches and descriptions of the types of equipment used, and records of his charitable contributions to individuals and institutions.

The Financial Papers series includes records of Pulitzer's investments in stocks and bonds as well as material relating to estates and trusts set up by Pulitzer and his father.