Prelude and Fugue in F-sharp major, BWV 856

The Well-Tempered Clavier, BWV 846–893, is a collection of two series of Preludes and Fugues in all 24 major and minor keys, composed for solo keyboard by Johann Sebastian Bach. In the German of Bach's time Clavier (keyboard) was a generic name indicating a variety of keyboard instruments, most typically a harpsichord or clavichord – but not excluding an organ either.