The Memorial Library of Music is a collection of printed and manuscript scores and composers' letters, dating primarily from the 18th and 19th centuries, but ranging into both the 17th and 20th centuries. Musical genres range from intimate piano works and country dance music to large-scale orchestral and vocal works, with a strong emphasis on opera. Many of the scores are autographs or inscribed by the composer. The original collection was created by George T. Keating and conceived as part of Stanford University's memorial to alumni who gave their lives in World War II. The Music Library actively adds works to the collection, particularly 18th and 19th century operatic works. A guide to the initial collection was completed by Nathan van Patten, professor of bibliography in 1950, and has been heavily annotated over the years. A partial online version is also available. Newer additions are cataloged separately and appear in Stanford's online catalog. Adminstrative files for the collection are available in a separate online collection.