The collection consists primarily of manuscripts and correspondence of McCoy. The manuscripts range from his writings as an investigative reporter in the early 1900s to his later works as novelist, biographer, and children's author under the name of Ellery Queen, Jr. Included are typescripts, outlines, and manuscript notes for three nonfiction works, 10 mystery novels, 25 short stories, approximately 87 articles, several poems, as well as autobiographical and miscellaneous notes. Among the published titles are How Prayer Helps Me, Odyssey of an American Family, The Black Dog Mystery, The Mystery at Pickle Point, and The White Elephant Mystery. Also included are a series of articles about Ireland, and articles on his investigation of the Florida penal system which resulted in the 1922 Pulitzer Prize for the New York World. McCoy's correspondence includes a few letters of such notables as George Ade, John F. Kennedy, Don Marquis, H. L. Mencken, Thornton Wilder, Booth Tarkington; and greater numbers from Guy Pene DuBois, Ella Neely McCoy, Harold Montanye (McCoy's frequent co-author), George Worts, as well as many libraries, institutions, friends, and family. In addition, there are drawings, documents, memorabilia, photographs, two scrapbooks, tearsheets, and reviews by and about McCoy. The section devoted to papers of other persons includes manuscripts and correspondence of George Baker, George Hamid, Ella Neely McCoy (papers and illustrations for her children's books), Ellery Queen, Jr., and Nicol Smith.