Sol and Luna constitute one of the most structurally generative symbol-pairs in the depth-psychological reading of alchemical tradition. Within this corpus the dyad does not function as mere planetary allegory but as the primary iconographic vehicle for articulating the opposition between consciousness and unconscious, masculine and feminine, active and receptive, spirit and soul. Jung, whose Mysterium Coniunctionis furnishes the richest vein of commentary, reads Sol as the ego and its field of illuminated awareness — the solar principle that ‘knowingly sundered subject and object’ — while Luna absorbs the anima, the shadow-contaminated unconscious, and the plurality of archetypes that consciousness cannot contain. The coniunctio of Sol and Luna, enacted in the Rosarium Philosophorum imagery as a royal marriage of brother and sister, stands for the individuation telos: a union that generates a third, the filius philosophorum or lapis, surpassing both parents. Edinger, following Jung, maps the dissolving of Sol and Luna in the mercurial waters onto the analytic dissolution of fixed ego-attitudes. Abraham’s lexicographical work traces the chemical substrate — mercury’s capacity to amalgamate gold (Sol) and silver (Luna) — while also noting that no chemical wedding proceeds without a third mediating principle. Moore, reading Ficino, situates Sol and Luna within a broader planetary psychology in which their complementarity governs the timing and embodiment of psychic life. The central tension across the corpus is whether the pair should be read primarily as a cosmological duality, a psychological polarity, or a soteriological drama.