In 1722, when Johann Sebastian Bach lived in Köthen, Germany, he published a book of preludes and fugues in all 24 major and minor keys. This collection became known as The Well-Tempered Clavier, Book One, BWV 846-869. About two decades later, Bach compiled a second book in Leipzig, which became known as The Well-Tempered Clavier, Book Two, BWV 870-893. Bach intended these pieces for the clavier, which includes the harpsichord, clavichord, and organ. Despite this unclarity, these pieces are regarded as some of the most important works in the history of Western classical music. In this broadcast, Joanna MacGregor plays Preludes and Fugues Nos. 13 to 24 (BWV 858-869) from Book One of Bach’s Well-Tempered Clavier, recorded at the Palau Güell in Barcelona, Spain, in 2010.