Correspondence, manuscripts, documents, notebooks, memorabilia, a tape cassette, photographs, and printed materials. The collection is primarily correspondence files, both personal and professional, along with book reviews, awards and diplomas, letters of condolence on his death, clippings, and correspondence, manuscripts and printed materials relating to THE STREAM OF HISTORY. The correspondence relates specifically to the third edition. The manuscripts are typed and holograph inserts for the third edition and possibly for the second edition as well. Among the manuscripts are twenty-two notebooks containing holograph notes and drafts of chapters. The printed material consists of one copy of THE STREAM OF HISTORY, 1934 edition.

Letters written to MacAlarney from well-known literary figures such as Franklin P. Adams, Irving Bacheller, Henry Arthur Jones, Joseph Hergesheimer, Rose O'Neill, and Gilbert Parker. Many of the letters concern the use of writers' stories or books for motion picture production. Other letters concern publication in the LADIES HOME JOURNAL.