The Requiem was Mozart's final work, composed during the illness--probably a form of rheumatic fever, and almost certainly not poisoning by Salieri or anyone else--that took his life on December 5, 1791. He had completed much of it, and sketched out most of the remainder; the score was finished by his friend and student Franz Xavier Süssmayr. This is a rich, moving work, notable for such exquisite moments as the "Lacrimosa," and displaying Mozart's grasp of vocal writing to the fullest. The Dover edition of the full orchestral score is, like almost all of their publications of this sort, a reprint of an out-of-copyright score. Because it does display all the orchestral parts, it won't be suitable for use by the average church organist, but it should prove very useful to singers and the general music lover.