The collection contains research files, interviews, correspondence, writings, and other materials relating to Gilbert A. Harrison's biography of Thornton Wilder, The Enthusiast: A Life of Thornton Wilder (1983). Harrison's research files, which include notes, photocopies of correspondence and writings, and clippings, make up the bulk of the collection. In addition to the research files, there are audio recordings of interviews with members of the Wilder family and others, such as Alfred Hitchcock and Lillian Gish, correspondence with Wilder family, scholars, and publishers, a corrected draft of the biography, and reviews. Other materials include biographical information, a copy of Wilder's will, and photographs.