Who composed 'The Well-Tempered Clavier'?

Johann Sebastian Bach composed The Well-Tempered Clavier. The monumental collection consists of two books, each containing 24 preludes and fugues in all major and minor keys.

Bach completed the first book in 1722 while working in Köthen, and he assembled the second book around 1742 in Leipzig. Together, the 48 pairs demonstrate how keyboard music can explore every key while combining technical discipline with extraordinary expressive variety. Bach described the first book as music for study and enjoyment, useful to learners and experienced musicians alike.

The title refers to a tuning approach that made it practical to play in all keys, although it does not necessarily mean modern equal temperament. The work is written for a keyboard instrument, probably harpsichord or clavichord, rather than specifically for piano. A frequent mistake is calling it a single composition: it is a two-volume cycle of 48 preludes paired with 48 fugues.