In this dissertation, I systematize transformations among chords, referential collections, and their constituent subsets, as exemplified in analyses of music by Gabriel Fauré, Claude Debussy, and Lili Boulanger. I characterize the effect of these transformations by supplanting notions of consonance and dissonance with a physics metaphor—the dichotomy and interdependence of centripetal and centrifugal force—to emphasize transformational processes over synchronic constructs, particularly notions of distance. Drawing from intercardinal voice-leading principles of transformational theory and graphical models of neo-Riemannian theory, I demystify harmonic/tonal practices salient in early twentieth-century French music, connect such practices with those of preceding tonal/evolutionary stages, and posit the effect of these practices in a way that reflects their intrinsically diachronic, centrifugal nature. I ultimately offer what I call “Collection Space”—a parsimonious intercardinal voice-leading space for maximally and nearly even sets—as a representative transformational space of French scalar tonality, analogized with the pan-triadic and Tristan-genus systems. My findings yield a revitalized approach to analyzing works by Debussy and Fauré as well as provide a rigorous analytical account of Lili Boulanger’s music hitherto unexplored.