Of the many composers in the Western classical tradition who celebrated the marriage between psyche and sound, those explored in this book followed the lines diverging from Wagner in philosophizing the nature of desire in music. This book offers two new theories of tonal functionality in the music of the first half of the twentieth century that seek to explain its psychological complexities. First, the book further develops Riemann’s three diatonic chord functions, extending them to account for chromatic chord progression and substitution. The three functions (tonic, subdominant, and dominant) are compared to Jacques Lacan’s twin concepts of metaphor and metonymy, which drive the apparatus of human desire. Second, the book develops a technique for analyzing the drives that pull chromatic music in multiple directions simultaneously, creating a libidinal surface that mirrors the tensions of the psyche found in Schopenhauer, Freud, and the post-Freudians Lacan, Lyotard, and Deleuze. The harmonic models are tested in psychologically challenging pieces of music by post-Wagnerian composers. From the obsession with death and mourning in Suk’s Asrael Symphony to an exploration of “perversion” in Strauss’s Elektra, from the post-Kantian transcendentalism of Ives’s Concord Sonata to the “Accelerationism” of Skryabin’s late piano works, and from the Sufi mysticism of Szymanowski’s Song of the Night to the failed fantasy of the American dream in Copland’s The Tender Land, the book cuts a path through the dense forests of chromatic complexity and digs deep into the psychological makeup of post-Wagnerian psychodynamic music.