Contains Rachmaninoff's most famous piano piece, the Prelude in C-sharp minor. This paired with the ten pieces from opus 23 provide the advanced pianist a newly-engraved and researched edition of the first half of the composer'soutput of piano preludes. Audio is accessed online using the unique code inside the book and can be streamed or downloaded. The audio files include PLAYBACK+, a multi-functional audio player that allows you to slow downaudio without changing pitch, set loop points, change keys, and pan left or right.