The majority of the collection is made up of Harnack's literary manuscripts, with holograph and typescript drafts of his books, poetry, plays, and short stories. There are drafts, galley proofs, and printers' typescripts of We Have All Gone Away; The Work of an Ancient Hand, Love and Be Silent; Limits of the Land; Under My Wings Everything Prospers; Persian Lions, Persian Lambs; Memoirs of a Farmboy Radical; and The Attic. Finally, the collection contains materials ranging from correspondence, reviews, and biographical materials to royalty statements. Included in the 1996 Addendum is "Teenagers Helping in Cornfields," the first piece for which Harnack received payment. He was paid five dollars for the essay. In the 2001 Addendum is a model newspaper created by Harnack as a child in the nineteen thirties.

Curtis Harnack began giving his papers to the University of Iowa Libraries in 1962 and has continued to add to the collection over the years. Parts of this collection are under seal and currently unavailable for research.