The Piano Sonata op. 101 marks the transition to Beethoven's late works. The composer's increasing deafness was already manifesting itself in such a marked way that he no longer dared to appear publicly as a pianist. In this sonata he experimented with unusual harmonies, broke with form, gave detailed German headings for the movements, and for the first time also used a note so unheard of that it was not even on most of the contemporary pianos: the low counter E. The editors have undertaken a thorough revision of our edition and our catalogue now offers a single edition of this sonata.