The unio mentalis occupies a structurally pivotal position in the depth-psychological corpus, functioning as the first and indispensable stage of Gerhard Dorn’s tripartite coniunctio, through which Jung mapped the alchemical opus onto the individuation process. In Mysterium Coniunctionis, Jung defines it as the attainment of full self-knowledge — the separation of mind from the body’s affective disturbances — which must precede any reunion with physical existence and, ultimately, with the unus mundus. Edinger’s Mysterium Lectures render this schema accessible through pedagogical clarity, tracking the unio mentalis as the moment when soul and spirit are reunited after differentiation from world and body, corresponding to the nigredo’s completion and the subsequent separatio of the two sulphurs. Hillman reorients the term decisively: rather than a spiritualizing withdrawal, the unio mentalis becomes for him the marriage of logos and psyche that constitutes psychology itself — a blue, Dionysian, aesthetically alive state identified with the caelum and the albedo. This Hillmanian reading resists the transcendentalist drift in Jung and insists on the imaginative, even erotic, character of the achievement. The central tension in the corpus, then, is between Jung’s phenomenological sobriety — the unio mentalis as a stage to be surpassed en route to embodied wholeness — and Hillman’s imaginal radicalism, which makes it the telos of psychological seeing.