The Orgelbüchlein BWV 599−644 is a set of 46 chorale preludes for organ — one of them is given in two versions — by Johann Sebastian Bach. All but three were written between 1708 and 1717 when Bach served as organist to the ducal court in Weimar; the remainder and a short two-bar fragment came no earlier than 1726, after the composer’s appointment as cantor at the Thomasschule in Leipzig.

Johann Sebastian Bach was a German composer and musician of the late Baroque period. He is known for his prolific authorship of music across a variety of instruments and forms, including; orchestral music such as the Brandenburg Concertos; solo instrumental works such as the cello suites and sonatas and partitas for solo violin; keyboard works such as the Goldberg Variations and The Well-Tempered Clavier; organ works such as the Schubler Chorales and the Toccata and Fugue in D minor; and choral works such as the St Matthew Passion and the Mass in B minor. Since the 19th-century Bach Revival, he has been generally regarded as one of the greatest composers in the history of Western music.