The collection is composed of a great deal of material that had been placed by Cabell in books that made up his personal library which numbered about 3,000 volumes and was donated to the library in the 1970s.

The collection includes correspondence with a number of noted American and British writers of the 20th century including H.L. Mencken, Ellen Glasgow, Sinclair Lewis, and Theodore Dreiser. There is also correspondence with family, friends, editors and publishers.

The collection also contains manuscripts of Cabell's work dating primarily from 1900 through 1930. Published reviews and criticisms of Cabell's work by various editors and writers is also included. The papers also contain a large collection of periodicals where Cabell's essays, reviews and fiction were published. Published and unpublished dramatic and musical interpretations of Cabell's work by others is included in the collection. Newspaper clippings, photographs, periodicals, criticisms, printed material, and publishers' agreements and statements of sales are also found in the collection. The collection also contains notebooks and scrapbooks compiled by Cabell documenting his early years as a writer.

The papers dating from 1963-1971 of the Cabell Society and correspondence between its founders is included in the collection as well as materials concerning Between Friends: Letters of James Branch Cabell and Others which was published in 1962.

Much of the material in Series I, II, III and VIII was taken from the nearly 3,000 volumes in Cabell's personal library. Cabell placed letters, newspaper clippings, photographs, illustrations, typed and written revisions of his works and other memorabilia in his books. In 1967, Cabell's library was cataloged by then doctoral student Jean Maurice Duke. He assigned each volume a "Duke" number and gave a description of each book and its contents. Prof. Duke would later serve as a long time faculty member of VCU's English Department.

In the 1970s his library (some 3,000 volumes) was moved from his home on Monument Avenue to VCU's James Branch Cabell Library. A sizable portion of that material was laminated at the Barrow lab at the Virginia State Library, paid for by Margaret Freeman Cabell.

Items taken from Cabell's library will have a Duke number written in pencil on it, indicating what volume the material was taken from. See James Branch Cabell's Library: A Catalogue by Jean Maurice Duke to determine from which book the item came.