The Moldenhauer Archives....

The Moldenhauer Archives at the Library of Congress contain approximately 3,500 items documenting the history of Western music from the medieval period through the modern era and is the richest composite gift of musical documents ever received by the Library. Before his death, Hans Moldenhauer (1906-1987) established a directive and provided funds for the Library of Congress to publish The Rosaleen Moldenhauer Memorial: Music History from Primary Sources: a Guide to the Moldenhauer Archives (2000). The book features a series of essays by musicologists discussing individual items from the Archives and contains a comprehensive inventory of the Moldenhauer Archives that are held in ten institutions worldwide.
This online presentation includes representative examples of more than 130 items from the Archives including many complete works and, as a special presentation, an electronic version of the book's text, which is intended to replace the printed edition. In addition, the book’s inventory of the Archives appears as a finding aid.
http://memory.loc.gov/ammem/collections/moldenhauer/