Neither the Prelude nor the Fugue is by Bach. The Prelude is by Johann Christoph Dretzel, a pupil of Bach, and was published as one of the pieces in Divertimento Armonico (1736-43). The composer of the Fugue is still unknown. The source material is a manuscript by Schelble, a conductor in Frankfurt who contributed to the 19th-century Bach Renaissance, and his pupil Gleichauf. It was included in the old complete edition under the heading "probably authentic."

Indeed, there are elements that recall Bach's style. The dramatic development of the Prelude is reminiscent of the middle section of the Chromatic Fantasia, BWV 903/1. Passagework carried by both hands frequently pauses on chords and then cascades downwards. Through the contrast between sections confined to a very narrow range and those that suddenly expand across the full width of the keyboard, a pseudo-variation in textural density is achieved, despite the monophonic nature.

The Fugue's subject contains two motifs of differing tempi, which, combined with the suspended countersubject, create an appealing sound.

Between the relatively long subject expositions, episodes featuring short, successive cadences are introduced, utilizing motifs from the subject. Here, keys shift rapidly, mediated by relationships of a fifth, parallel keys, and simple sequential progressions. However, these modulations are mostly limited to the dominant or subdominant of parallel major/minor keys, not venturing into very distant keys. Eventually, around two-thirds of the way through the piece, the inverted subject appears. The sixteenth-note motif from the latter half of the subject is driven into the high register, followed by a series of melodic minor scales, but this tension does not last long and is soon swept away by arpeggiated passagework. A pedal point spanning over 10 measures from bar 91 would likely sound even more effective on an organ, but it is entirely playable on the piano. The inverted subject reappears in the right hand, but it gently returns to the middle register as if drawn by the low notes in the left hand. The final section of the conclusion repeats the first half of the subject's motif in unison with both hands and concludes with simple chords.

While the Fugue incorporates various ingenious devices, it is regrettable that it does not fully satisfy the demands of its extensive scale, exceeding 100 measures. Particularly, the 30 measures following the appearance of the inverted subject and the subsequent descending passagework abandon contrapuntal and motivic development. Regardless of the true composer, the concluding section is somewhat disappointing, but the majestic development in the first half makes it a work well worth performing.