The Well-Tempered Clavier

Two volumes of preludes and fugues in all 24 keys, written for keyboard by Johann Sebastian Bach "for the profit and use of musical youth desirous of learning and especially for the pastime of those already skilled in this study". The first volume came out in 1722, when Bach was aged 37, and the second twenty years later. Both bear an unparalleled variety and quality of inventiveness, feeling, and beauty.