The Thirty-three Variations on a Waltz by Diabelli, Op. 120, represent Beethoven's most extraordinary achievement in the art of variation-writing. In their originality and power of invention, they stand beside other late Beethoven masterpieces such as the Ninth Symphony, the Missa Solemnis, and the last quartets. William Kinderman's study of the compositional history of the work includes the first extended investigation and reconstruction of the sketches and drafts, and reveals, contrary to earlier views of its chronology, that it was actually begun in 1819, then put aside, and completed in 18