According to Norris, the manuscript, containing all the original orchestration for the work and missing the first four pages and title page, is "unquestionably genuine."
Rachmaninoff's Second Symphony, his most popular and frequently played orchestral work, was completed in 1907, when the composer was in staying in Dresden. The symphony's first two performances, conducted by the composer, were in St. Petersburg in January of 1908. The manuscript had not been accounted for since it was used to prepare the first published edition of the score later that year.
The manuscript, which is thought to be worth between $550,000 and $920,000, will be auctioned by Sotheby's in London in December. It will be on view at the auction house's New York City location from November 16-19.