Frederic Chopin's Impromptus For The Piano. This edition contains the four Chopin impromptus: No. 1 in A-flat major, Op. 29 No. 2 in F-sharp major, Op. 36 No. 3 in G-flat major, Op. 51 Fantaisie-Impromptu in C-sharp minor, Op. posth. 66