Nun komm, der Heiden Heiland, BWV 599
...
Ach wie flüchtig, ach wie nichtig, BWV 644

Bach composed the Orgel-Büchlein while working as court organist in Weimar from 1713 to 1717. He had planned 164 chorale preludes and noted all their titles, but was finally to complete only forty-five of them; they are arranged according to the ecclesiastical year. The pedal line is given an independent role in all of these works and is thus not intended as an accompaniment. The type of chorale prelude that Bach uses in this volume is unique: not only are there no introductions or interludes, no pre-imitations as was the case with Buxtehude and Pachelbel, but also the chorale melody begins immediately and almost always in the upper voice. Every prelude contains one or more motifs, while canonic imitation is used in eight of them; the melody is also richly ornamented in a number of the chorales. Most of these works originated in Weimar, at a time when Bach was able to devote himself completely to composing for the organ. We find the fundamental principle that is linked to almost all of Bach’s works in the preface to the Orgel-Büchlein in the words Soli Deo Gloria (to God alone the glory): it was Bach’s firm belief that music mirrors the perfection of God’s creation. It is also important to note that Bach used his music largely for pedagogical and didactic purposes: the Orgel-Büchlein is an ideal example of this, a combination of healthy ambition and divine mastery. This volume has not been called Bach’s musical dictionary and the bible of organ literature for no reason.