Which composer wrote the piano cycle The Well-Tempered Clavier, containing two books of 24 preludes and fugues?

Johann Sebastian Bach wrote The Well-Tempered Clavier, containing two books of 24 preludes and fugues.

Bach’s first book was completed in 1722, while the second was compiled around 1742. Each book travels through all 24 major and minor keys, pairing a prelude with a fugue in each key. Together, the two books contain 48 paired sets, not merely 24 pieces.

The title refers to a tuning system that allowed music to work across the keys, though scholars debate exactly which temperament Bach intended. “Well-tempered” should not automatically be treated as identical to modern equal temperament.

The collection served both artistic and educational purposes. Bach described it as useful for the profit and use of musical youth, and the pieces remain central to keyboard study. The work is sometimes confused with Chopin’s later sets of 24 Preludes, but Chopin did not write The Well-Tempered Clavier.