The collection consists of Sidney Robertson Cowell's personal papers that document her life and work. It includes correspondence with family, friends and colleagues, inlcuding husband Henry Cowell, Ansel Adams, Ernst Bacon, Suzanne Bloch, Bertrand Bronson, Frank Brown, John Cage, Adrian Dornbush, Sam Eskin, Warde Ford, Grete Franke, Alfred Frankenstein, Lou Harrison, H. Wiley Hitchcock, Maud Karpeles, John Kirkpatrick, William Lichtenwanger, John Lomax, Dorothy Maynor, Colin McPhee, Laurence Powell, Bruce Saylor, Charles Seeger, Pete Seeger, Peggy Seeger, Nicolas Slonimsky, Stephen Spackman, Virgil Thomson, Margaret Valiant, Robert Van Hyning, Hugo Weisgall, Yehudi Wyner, and Shinʼichi Yuize. The collection contains materials that document her field recording projects and trips during all phases of her career, including her work with the Resettlement Administration; the W.P.A. California Folk Music Project, which she conceived and directed; the Appalachian collecting trip with Maud Karpeles; the Wolf River/Ford-Walker family, Cape Breton Island, and Aran Islands recording trips; and her travels to Asia and the Middle East with Henry Cowell, during which she recorded many traditional musicians. In addition, it contains published and unpublished written material by Sidney Robertson Cowell, including books, articles, essays, reviews, reports and papers; autobiographical narratives and essays relating to her career and to her personal life; project proposals; and teaching materials. There is material related to Henry Cowell, including transcripts of recorded biographical narratives that Sidney made for a biography of Henry that was never completed; narratives and articles about Henry written by Sidney and others; articles on music written by Henry; a selection of folk songs with piano settings by Henry Cowell in his own hand, and photocopies of a small collection of Henry Cowell holographs, some annotated by Sidney. The collection also contains materials relating to personal and professional interests, including schools where Sidney Robertson Cowell taught, conferences in which she was involved, her travels both alone and with Henry, personal and professional relationships with individuals such as Percy Grainger, John Cage and Roland Hayes, and materials relating to the Cowell's book on Charles Ives. It also contains photographs and song sheets and song books.