Summary

Chapter XVII demonstrates the practical flexibility of Messiaen's modes of limited transpositions through three types of modal relationships: mixing modes with major tonality, modulating a mode to itself through transposition changes, and modulating between different modes. Despite their symmetrical properties and theoretical existence outside traditional tonality, the modes can suggest specific tonal centers through emphasis of particular pitches, use of traditional harmonic functions (especially dominant seventh chords), or mixture with non-modal materials. The chapter reveals that modal practice in Messiaen's hands remains pragmatic rather than dogmatic—modes function as harmonic resources that can be deployed in various contexts according to compositional needs, whether to provide coloristic enrichment within tonal frameworks, to create harmonic motion through transposition, or to access diverse harmonic palettes through inter-modal modulation. This flexibility distinguishes Messiaen's modal practice from more rigid systematic approaches, allowing the modes to serve expressive and formal goals while maintaining their characteristic symmetrical properties and distinctive sonorities.