After her landmark recordings, the international music publisher C. F. Peters commissioned Ruth Laredo to edit a new Urtext edition of the complete 24 Preludes of Rachmaninoff, which were published in 1981 (Op. 3, No. 2), 1985 (Op. 23) and 1991 (Op. 32). Laredo thought that many of the markings in the commonly used Rachmaninoff editions were not those of the composer; after studying original manuscripts, which she found in the Library of Congress and in the Rachmaninoff archive in Washington, D.C., and later in the Glinka Museum during her tour to Russia in 1989, her suspicions were confirmed. Her editions were much closer to the composer's original manuscripts.