J. S. Bach - The Well-Tempered Clavier BWV 846-869

The Well-Tempered Clavier, BWV 846–893, is two sets of preludes and fugues in all 24 major and minor keys for keyboard by Johann Sebastian Bach. In the composer's time clavier, meaning keyboard, referred to a variety of instruments, most typically the harpsichord or clavichord but not excluding the organ.