The Orgelbüchlein, translated as 'Little Organ Book', is a set of 46 chorale preludes written by Johann Sebastian Bach mostly during his tenure as organist in the court of Weimar, from 1708 to 1717 (three preludes and some fragments were added more than 10 years later). These chorale preludes are considered Bach's first masterpieces for the instrument, displaying a mature compositional style in contrast with his previous organ works. Most of the individual pieces are based on a Lutheran hymn, creating an unifying line. However, Bach applies diverse treatments to the hymns' melodies: there are short preludes in three parts + pedal, pieces that require more than one keyboardist and display a high level of ornamentation, and even a trio sonata. The collection is defined by Bach himself in the title page as '[a book] in which a beginning organist receives given instruction as to performing a chorale in a multitude of ways while achieving mastery in the study of the pedal, since in the chorales contained herein the pedal is treated entirely obbligato'. As many of Bach's collections of works, the Orgelbüchlein serves not only as a set of organ music for religious services, but also as a compendium of compositional styles and a pedagogical tool.
