Johann Sebastian Bach

Johann Sebastian Bach (1685-1750) was better known as a virtuoso organist than as a composer in his day. His sacred music, organ and choral works, and other instrumental music had an enthusiasm and seeming freedom that concealed immense rigor. Bach's use of counterpoint was brilliant and innovative, and the immense complexities of his compositional style -- which often included religious and numerological symbols that seem to fit perfectly together in a profound puzzle of special codes -- still amaze musicians today. Many consider him the greatest composer of all time.

The first book of Bach's Das Wohltemperierte Klavier (The Well-Tempered Clavier) was complete by 1722. Bach gave the present title to the work, which was composed "for the use and practice of musical youth eager to learn and for the amusement of those already skilled in this study." Bach composed a paired Prelude and Fugue in each of the 24 keys to demonstrate the viability of the new "equal-temperament" system, which allows one to play in all keys without producing out-of-tune intervals, as happened with Pythagorean and "mean tone" tunings. Furthermore, the pieces are as much compositional studies as keyboard works.

Twenty years later, Bach assembled another set of preludes and fugues. The title page is missing from the manuscript, but its similarity to the "first" book of The Well-Tempered Clavier led editors to entitle it "Book II." Bach worked on the second book over a long period of time, even reworking pieces he had written for other purposes, as he had in the first book. Some of the preludes and fugues date from the 1720s. Possibly the most substantial revision for the second book was to No. 3, in C sharp major, which was originally in C major. Fugues Nos. 15 and 17 survive in earlier versions in which they are connected with different preludes than we find in The Well-Tempered Clavier.

There are many musical differences between the works of Book II and those of Book I. The preludes in the second group explore a greater range of forms and styles than do the earlier examples. Most striking are the experiments in the style of the Italian bipartite keyboard sonata, codified by Domenico Scarlatti. Like earlier dance movements, these consist of two repeated sections. Some of the "sonata" preludes in Book II, such as Nos. 5, 12, and 21, feature a recapitulation of the opening material, while others (Nos. 10 and 15) have parallel closing sections. Prelude No. 17 is an Italian concert-ritornello movement; Nos. 13 and 23 also display concerto traits. The tenth is a two-part invention and Nos. 4 and 14 are ariosos. Those that are clearly derived form dance forms -- No. 5 from the gigue and No. 8 from the allemande -- lack the traditional binary form.

Like the fugues of Book I, those of Book II employ every device of formal fugue writing. In terms of compositional economy, No. 2 of the second Book is a masterpiece -- in the first 28 measures there are 24 statements of the one-measure subject, producing almost painfully dense counterpoint. Fifteen of the fugues are in three voices; nine are in four. Four of these (Nos. 4, 17, 18 and 23) are double fugues and No. 14 is a triple fugue, the third subject of which recalls a subject from the C sharp minor Fugue of Book I. In general, the fugues of Book II are thematically more restrained than those of Book I. Instead, Bach seems to experiment with the contrapuntal potential inherent in each of the fugue subjects.

This determined, forward-pressing but not too speedy two-part invention serves as the final prelude in Bach's monumental Well-Tempered Clavier. The lower voice imitates the upper at an octave's interval, and successive entries shift through related keys. The fugue announces itself with a passepied theme in the alto voice, with soprano and bass subsequently joining in. A countersubject accompanies these entries, without significantly differentiating itself from the main theme. A wholly new subject does arrive in the bass, initially as an accompaniment to the second entrance of the main subject, and thereafter serves as the principal theme's constant companion.

Although originally created for Keyboard (Harpsichord), I created this orchestral harp arrangement to highlight the light and airy arpeggios of the prelude as well as the delicate interplay between the voices in the fugue.