The Well-Tempered Clavier is a kind of encyclopedia of fugue composition, in which the greatest master of the genre tried out almost every technique and style available to it. It falls into two books, the first gathered together in 1722, the second twenty-two years later. Each book presents, systematically, a fugue in every key and in both major and minor modes: 12 keys × 2 modes × 2 books — that’s 48 fugues in all. Each fugue is preceded by an introductory piece, or prelude, in the same key and mode (forty-eight more pieces!).

Some of the fugues give the impression of stern regimentation, some are airy and serene; some echo counterpoint from a century before, others sound like up-to-date dances; some even seem to aim for comic effect. Bach was unsurpassed in the expressive variety he could milk from fugal techniques.

Clavier (or Klavier) is today the German word for piano. In Bach’s time it referred to a variety of keyboard instruments, including the harpsichord and the very earliest pianos (but not including the church organ). The term well-tempered refers to a particular way of tuning the keyboard, among the several employed in the eighteenth century. The Well-Tempered Clavier was probably played in Bach’s time on various instruments, but most often on harpsichord. Our prelude and fugue are played on piano by a modern master of Bach interpretation, Glenn Gould (see page 131).

Prelude Like the fugues, the preludes in The Well-Tempered Clavier display a wide variety of moods, from gentle and lyrical to aggressive and showy, and they explore many musical textures (though usually not the imitative polyphony that features in the fugues to follow). Each prelude tends to occupy itself in an almost obsessive manner with a single musical gesture, repeating it over and over across shifting harmonies. The preludes are, in their different way, systematic like the fugues that follow.

The most famous of them — and also one of the easiest for the novice pianist to work through — is the first, in C major. Its basic gesture is an upward-moving arpeggio — that is, a chord “broken” so that its pitches are played in quick succession rather than simultaneously. The wonder of this simple prelude is the rich array of chords Bach devised for it. We feel at its end as if we have taken a harmonic journey, ranging away from our starting point, exploring some rather rocky pathways (that is, dissonant harmonies), and finally — satisfyingly — arriving back home.

Fugue Perhaps because this fugue takes pride of place in The Well-Tempered Clavier, Bach crafts it with extraordinary economy and single-mindedness. There are no episodes here, and there is no countersubject to speak of. There are only incessant entries of the subject — twenty-four in all. (Was Bach, who loved number games, referring to the number of fugues in the whole of Book 1?) Many of them overlap in stretto fashion.

The subject is introduced in a spacious exposition — soprano, tenor, and bass follow the alto at even time intervals. The subject moves stepwise up the scale in even rhythms at first, only to reverse course with a quick twist downward. Listen carefully for this twist; it will help you pick out the many subject entries to come. (The whole subject is shown in Listening Chart 6.)

After the exposition, however, all bets are off, fugally speaking. Instead of the more usual episodes alternating with orderly entries of the subject, this fugue is all about stretto. The first stretto comes as soon as the exposition is complete, with two voices overlapping, and from then on entries begin to pile up.

But an overall order underlies all these strettos. The fugue comes, exactly at its midpoint, to a strong cadence on a key different from our starting key, and in the minor mode. This articulates but does not stop the action, as the stretto entries of the subject begin again immediately, back in the home key. Indeed, as if to counterbalance the clarity of the cadence, the entries here come faster than anywhere else in the fugue — eight of them in quick succession. At one moment four entries all overlap, the last beginning before the first has finished.

After this frenzy of entries, even a big cadence back in the home key takes a moment to sink in, as three more entries of the subject quickly follow it. The energy of all this finally comes to rest in the soprano voice, which at the very end floats beautifully up to the highest pitch we have heard.