The collection contains printed and photocopied manuscript music scores, negative photostats and microfilm of holograph music, correspondence, clippings, periodicals, articles, notebooks, programs, photographs, manuscript and typewritten journals, printed biographical sketches, bound and unbound scrapbooks, and a printed catalog of Koutzen's compositions. Much of the material in the subject file series is concerned with Koutzen's works The fatal oath and You never know. Notable correspondents include Serge Koussevitzky, Vincent Persichetti, Walter Piston, William Schuman, Josef Gingold, Gregor Piatigorsky, Leon Barzin and Thornton Wilder. The collection also contains correspondence from the Boston Symphony Orchestra, the Juilliard School of Music, the Manhattan Symphony Orchestra, the National Symphony Orchestra, and Koutzen's principal music publisher, General Music Publishing Co., Inc. In addition, the collection includes a modest acquisition of correspondence and music belonging to Koutzen's daughter, Nadia Koutzen, who had her own career as a solo violinist. Most of the correspondence is between Nadia and either Vincent Persichetti or Isaac Stern.