Interior Alchemy occupies a distinctive and contested position within the depth-psychology corpus, functioning simultaneously as historical practice, psychological metaphor, and contested philosophical program. Jung’s foundational contribution was to demonstrate that the alchemical opus — with its vessel, heat, transformation, and projected substances — described a parallel interior process: the artifex, projecting psychic contents into matter, undergoes the same purification and transformation he performs upon the chemical substrate. This reading, elaborated across Alchemical Studies, Psychology and Alchemy, and Mysterium Coniunctionis, established interior alchemy as a pre-scientific language for individuation. Hillman pushed this further, insisting that alchemical psychology was not merely a metaphor for intrapsychic change but a mode of attending to soul in matter and cosmos — the yellowing, whitening, and reddening as necessary stages in rescuing psychology from its own self-enclosure. Von Franz contributed careful attention to the sealed vessel as psychological container, linking introversion with the conditions necessary for transformation. The Daoist corpus, represented by Kohn, charts a parallel tradition of neidan (inner alchemy) operating through the body’s interior fires, deities, and cosmological correspondences. The sharpest theoretical challenge comes from Giegerich, who argues that Jung psychologized alchemy too quickly, confining its mercurial substance within the bottle of the personal unconscious and thus foreclosing the genuinely logical — not imaginal — revolution alchemy represented. Moore, more accessibly, recasts interior alchemy as a grammar for soulful engagement with ordinary work.