Key Concepts

This chapter introduces eight key concepts expanding Messiaen's harmonic vocabulary:

1. The Chord on the Dominant - A saturated harmonic structure containing all seven pitch-classes of the major scale, functioning as an enriched dominant sonority

2. The Chord of Resonance - A harmonic structure derived from the acoustically perceptible overtones of a low fundamental pitch, forming the basis of "natural harmony"

3. The Chord in Fourths - A harmonic structure built from stacked perfect and augmented fourths, abandoning tertian construction

4. Effects of Resonance - Compositional techniques employing chord clusters to simulate or evoke acoustic resonance phenomena

5. Clusters of Chords - Multiple chords sounding simultaneously, creating dense harmonic textures and coloristic stratifications

6. A Look at Other Styles - Analytical examination of how other composers' harmonic languages can be understood through Messiaen's theoretical framework

7. Natural Harmony - A conception of harmony as emerging from acoustic phenomena and spiritual aspiration rather than theoretical systems

8. A List of Connections of Chords - A systematic catalog of harmonic progressions demonstrating practical applications (Examples 230–301)