Approximately 12,000 letters to Allan Nevins from various correspondents including James Truslow Adams, Franklin Delano Roosevelt, Harry S. Truman, Willa Cather, Frances Folsom Cleveland, Van Wyck Brooks, Robert Frost, Newton D. Baker, Archibald MacLeish, John D. Rockefeller, Jr., Carl Sandburg, and Henry Wallace; notes and typescripts for Nevins' books including Emergence of Lincoln, The Ordeal of Democracy, Rockefeller, and History and Historians, with notes by editor Ray A. Billington; miscellaneous transcripts, clippings, newspapers, and photographs. Also, autograph letters and manuscripts by presidents, Civil War figures, financiers, politicians, and authors. There are also the Brand Whitlock World War I Diaries and letters to him by such people as Herbert Hoover, Gen. John J. Pershing, and others.

Correspondence relating to Erskine's various educational, musical and literary interests; manuscripts of his writings; lecture notes for college courses; souvenirs of his army service in World War I and his Columbia University professorship, and student papers from his own school and college days. Also, biographical file, scrapbooks, and articles.