Keyboard composers in various eras, such as J. S. Bach, Frédéric Chopin, and Dmitri Shostakovich, composed keyboard cycles with 24 preludes (along with fugues, in some cases), that pass through all major and minor keys. These mammoth cycles differ in how a progression of tonality is organized. Bach composed two books of The Well-Tempered Clavier (BWV 846-893), wherein each one made use of a continuous rising chromatic pattern, from C major to B minor through pairs consisting of a major and its tonic minor (i.e., C major, C minor, C# major, C# minor, etc.). Chopin and Shostakovich preferred their keyboard cycles (i.e., the former’s 24 Preludes and the latter’s 24 Preludes and Fugues) to navigate through the circle of 5ths in a clockwise motion, by pairs consisting of a major and its relative minor, from C major to D minor (i.e., C major, A minor, G major, E minor, etc.).
One practical reason for these long, extensive preludes for the keyboard is to warm up the keys for the ears. Unlike an instrumentalist, who may start with a short tuning routine, the keyboardist may use this opportunity for their, and the listeners’, ears to get acquainted to the tuning of the instrument. Preluding — the act of a keyboardist spinning out a prelude — does not pertain only to precomposed works. Rather, it can also loosely refer to an improvisatory habit, which can be further traced back to the unmeasured and measured preludes composed in the French claveçin school tradition. The spontaneous act of playing, without rhythmic rigidness, a prelude before the start of a piece has lost its conventional place in modern recitals (although one was seen in a documented recital given by Vladimir Horowitz, as he improvised some harmonic progressions before he began the first piece).
The improvised form of preluding, as free and casual as it seems, relies on the pianist’s sufficient knowledge and experience in understanding and expressing how tonality behaves. Tonality is a vast concept that can be broken down into fundamentals — such as the circle of 5ths, scales, chords, and cadences — to be emphasized in the context of keyboard harmony over the course of this chapter. But tonality does not stop after Chapter 1. Chapter 2 begins with 7th chords and further exploration of tonality, which leads towards a cadenza project that is a lot more ambitious than a prelude.
The student may find more gravitas from the baroque tradition in Chapter 1 (such as the usage of figured bass in Module 1.6 and the suggested materials for preluding in Module 1.9). These are by no means trying to replicate and cover all of what composers and performers would have done in an authentic period practice study. Rather, they open doors for modern pianists to apply learned keyboard skills in forms of improvisation that pay homage to one of the golden ages of improvisation in classical music.