This collection consists of extensive personal correspondence, concert documents, scores, manuscripts, recognition, primary publications, secondary publications, university papers, photographs, recordings, memorabilia and artifacts mainly relating to the private and professional lives of Gustav Mahler, Alfred Rosé, Arnold Rosé, Alma Rosé, Bruno Walter, Justine Rosé, and Maria Rosé. Other material relating to Alma Mahler-Werfel, Marie Mahler, Otto Mahler, Maria Rosé, Albine Adler, Dorothy Beswick Hetherington, Lorraine Busby, Jacob Dont, Martha Freud, R.A. Loederer, Nora Nathan, Richard Newman, Richard Strauss, and Arturo Toscanini are included. Also included are materials in the collection whose connection is unclear