The 46 pieces in the Orgelbüchlein (Little Organ Book) are examples of the organ chorale. Each is a setting of one stanza of a congregational hymn of the German Protestant Church. Bach composed nearly 150 chorale settings, including the third part of the Clavierübung, the six Schübler Chorales, and the Leipzig Chorales.

Organ chorales were previously made popular by composers such as Jan Pieterszoon Sweelinck, Samuel Scheidt, and Dietrich Buxtehude. Bach, inspired by the chorale texts as well as the works of the earlier masters, created artful gems of his own.

When Bach set out to compose the Orgelbüchlein around 1714, he wrote the titles of 161 different hymn tunes for 164 settings on 92 sheets of paper. The first 33 works in the book follow the order of the liturgical year, starting with Advent. The remaining 13 settings are chorales of faith relating to Christian life. Since Bach accepted a new job as court musician for Prince Leopold of Anhalt-Cöthen, which did not require playing such music, he never completed the book.

On the title page of the Orgelbüchlein, Bach wrote: "wherein the beginning organist may learn to perform chorales of every sort and also acquire facility in the use of the pedal which, in the chorales found herein, is handled entirely obbligato." If he intended these as pedagogical purposes, then the first statement seems more fitting than the second, since the chorales are not in order of technical difficulty. Perhaps Bach wrote the title page as a formal explanation of the contents rather than a statement of purpose.

Most of the chorales are of four-part texture with the melody in the soprano. One noteworthy exception is Christum wir sollen loben schon (Let Us Give Beauteous Praise to Christ), in which the choral tune is in the alto line. This particular chorale also includes the only example of double pedal in the Orgelbüchlein. Another chorale atypical of the collection is Ich ruf zu dir, Herr Jesu Christ (I Call to You, Lord Jesus Christ), which is the only prelude with three voices.

Bach related some words in the texts to certain musical motifs. Words such as "joy," "sorrow," and "arising" particularly stirred his imagination. In O Lamm Gottes, unschuldig (O Lamb of God, Slaughtered), the aura of sadness is reinforced by recurring slurred notes often associated with grief. The descending leap in the pedal line in Durch Adams Fall (By Adam's Fall) symbolizes the fall of Adam. In contrast, the upward leaps in the pedal line of Erstanden ist der Heilge Christ (The Holy Christ Has Arisen) represent Christ's resurrection. Bach used these motifs to unify the composition and to present one main idea for each particular setting.

The Orgelbüchlein is an invaluable collection of miniature masterpieces that both reveals the influence of previous composers and provided inspiration for future composers such as Johannes Brahms and Felix Mendelssohn. The organ chorale as a form was further refined as a result of Bach's masterful contribution.