Alchemical transformation occupies a central and generative position in the depth-psychology corpus, functioning simultaneously as historical phenomenon, psychological metaphor, and living process of the psyche. Jung’s decisive move—articulated across the Collected Works, especially in Alchemical Studies, Psychology and Alchemy, and Mysterium Coniunctionis—was to read the alchemical opus not as proto-chemistry but as an unwitting projection of the individuation process: the transmutation of base matter into the Philosophers’ Stone mirrors the psyche’s movement from unconscious totality through differentiation toward conscious wholeness. Edward Edinger systematized this insight in Anatomy of the Psyche, cataloguing the major alchemical operations—calcinatio, solutio, coagulatio, mortificatio, sublimatio, separatio, coniunctio—as discrete yet overlapping stages of psychotherapeutic transformation. Marie-Louise von Franz deepened the symbolic archaeology, tracing alchemical imagery back through Gnostic, Egyptian, and Hermetic roots. James Hillman, characteristically contrarian, redirected the inquiry: where Jung and Edinger sought psychological parallels to alchemical process, Hillman insisted that alchemical language itself performs therapeutic work, that the imaginal specificity of sulfur, salt, and mercury is irreducible to generic developmental schemas. Tensions persist between literalist-historical readings of the tradition and its use as a projective screen for modern individuation theory, between the ascensionist spirituality Hillman critiques and the chthonic, nigredo-affirming strand he champions. For the depth-psychology reader, alchemical transformation remains the richest available vocabulary for psychic change that is neither linear nor moralistic.