GUIDE: Library of Congress. Music Division. Catalogue of opera librettos printed before 1800, prepared by Oscar George Theodore Sonneck. CRL Reference Folder #224 This is the collection of German businessman Albert Schatz of Rostock, containing 12,238 pieces. The entire history of opera from its beginning through the 19th century is represented, although the collection is particularly strong in German and Italian librettos of the 17th and 18th centuries. Not all of the items listed in the Sonneck catalog were reproduced in this set. The collection is arranged alphabetically by composer and title, and entries are numbered consecutively with Schatz numbers found in the Sonneck catalog.