This collection primarily consists of correspondence to and from Sidney Robertson Cowell concerning various personal and professional issues. Correspondents include Moe Asch, Ernst Bacon, Ernest Bloch, Suzanne Bloch, Bertrand Bronson, John Cage, Avery Claflin, Henry Cowell, Emma Dusenbury, Marjorie Edgar, Dora Edinger, Seamus Ennis, Alfred Frankenstein, R. Buckminster Fuller, Percy Grainger, Archie Green, Herbert Halpert, Wayland Hand, George Herzog, Kathryn Hulme, President Lyndon Johnson's staff, Maud Karpeles, Rae Korson, Alan Lomax, Irving Lowens, Margaret Mead, C. Robert Payne, Vivian Perlis, John Powell, Laurence Powell, Paul Radin, Vance Randolph, Charles Seeger, Pete Seeger, Harold Spivacke, Archer Taylor, Virgil Thomson, and Edward Weston. Some correspondence is accompanied by additional materials, including articles, journals, lists of songs, and clippings. The John Powell material consists of correspondence that discusses Powell's recent death and drafts of Powell's obituary written by Cowell. The Charles Seeger material includes correspondence about and written tributes for his upcoming eightieth birthday celebration.