The collection consists of correspondence, notebooks, manuscript drafts and typescripts, galley and page proofs of novels and plays, manuscript drafts and tear sheets of essays, writing notebooks, background files, financial records, and documents. Bound proofs have been catalogued and placed with the books. The collection is principally in the order established by MacInnes. The correspondence with his publisher is divided according to the publication to which it pertains, and most of the rest of the correspondence is filed with the manuscript drafts to which it was attached. The presence of correspondence is indicated in the register by an asterisk. The exceptions are letters to and from Elepeth Huxley, and letters from Robert Graves, Sidney Nolan, John Osborne, and Sir John Gielgud, which are indexed and filed at the beginning of the correspondence. Events in MacInnes' life that are documented in the collection are his early years in Brussels, his bankruptcy about 1960, his abortive trip to Africa in 1971 under the auspices of the British Council, and his hospital treatment during his final illness.

The Elizabeth Van Santvoord Papers represent a collection of her manuscript essays, poems and writing fragments.

The Frances Angevine Gray Keef Papers consist of two series: Personal Papers and Writings. Personal Papers includes correspondence between Keef and her family as well as several pieces of professional correspondence related to her career as a teacher and writer. This series also includes family photographs, of Keef as well as her immediate family between the late nineteenth century through the mid- twentieth century. The second series, Writings includes several examples of Keef's poetry, as well as essays and articles. This series also contains newspaper reviews and articles about Keef and her work.

The John Edward Masefield Papers are comprised of one box containing correspondence, poems, essays, and other prose works by John Masefield.

The collection consists of a group of manuscripts which formed the first and only issue of "The London Miscellany", a literary magazine which was never published, with the page proofs of the magazine and one letter to the editor, Sir John Stanier Waller, from John Heath-Stubbs. "The London Miscellany", was meant to provide a forum for young post-war writers.

The collection includes the correspondence and other papers of William Channing Gannett (1840-1923), who was a Unitarian minister in St. Paul, Minnesota (1877-1883) and Rochester, N.Y. (1889-1908). The correspondence to and from Mr. Gannett includes letters from Jane Addams, Abigail May Alcott, Susan B. Anthony, Samuel Longfellow, Elihu Root, Alphonso and William Howard Taft, Booker T. Washington, Frank Lloyd Wright and many Unitarian leaders of the late 1800s and early 1900s. There are also letters relating to the Western Unitarian Controversy, the education of the freedmen at Port Royal, the temperance crusade, Unity magazine, Unitarian church organization and membership, and to the editing of Unity Hymns and Chorals by Mr. Gannett and Frederick L. Hosmer. About 400 letters, dated 1875-1912, were added to the collection by Charles H. Lyttle and relate to the Western Unitarian Controversy.