Forgotten is the fact that Brian Hyer’s 1989 dissertation, so key to the renaissance of Hugo Riemann, had a Lacanian foundation. Building on this, Kenneth M. Smith re-evaluates tonal Riemannian ‘function’ as a linguistic unconscious flow that Lacan mapped as metaphor and metonymy, crucial to a subject’s formation. Aligned with Freud’s condensation and displacement, these two axes equate with chord substitution and combination, the former a primarily octatonic minor third transaction and the latter a discharge along the cycle of fifths and hexatonic major third progression. The author consolidates his findings by returning to the Prelude of Wagner’s Tristan and Isolde.