The Elmer T. Clark Collection reflects Clark's work as a writer, editor, and church historian. Record types include essays, articles, manuscripts for books, correspondence, and a collection of promotional materials -- posters, pamphlets, booklets -- for the Missionary Centenary in 1918. A few personal records, such as correspondence and wills, and an audiotape of an interview between Clark's wife, Mary Alva Clark, and Ellen Lasely are included as well. The Essays and Articles series contains a subseries of addresses delivered by various speakers at the Aldersgate Session of the General Missionary Council, Methodist Episcopal Church, South, in 1938. Clark and the other editors on the Journal and Letters of Francis Asbury publishing project corresponded with several outside researchers. That correspondence is included in the collection.

The collection consists of two manuscripts. Both manuscripts include a section called, "Circuit Rider, or Seven Sides of the Itinerancy." The theme of itinerancy is present throughout both manuscripts. The photocopy of the original manuscript is incomplete. Other topics within these manuscripts are sermons, sermon outlines, life during the Civil War, poems, and an obituary.

This collection is comprised of correspondence, sermons, clippings, articles, postcards, poems, and manuscripts. The manuscripts cover topics such as biographies, camp-meetings, history of the denomination, sermons and sermon notes, devotionals, and published texts.