'The Viennese oracle on the core literature of Haydn, Beethoven and Brahms,' is how The Philadelphia Inquirer has described the pianist Rudolf Buchbinder. It would be hard to find someone better qualified to record both Beethoven's '33 Diabelli Variations' - a towering landmark of the piano repertoire - and the briefer variations composed by some 50 of Beethoven's contemporaries at the invitation of Anton Diabelli, an enterprising Viennese publisher. The theme was a waltz written by Diabelli himself. Among the composers who took up the challenge were Franz Schubert, Franz Liszt, Carl Czerny, Johann Nepomuk Hummel, Ignaz Moscheles, V�clav Tom�sek and Franz Xaver Wolfgang Mozart.