The term ‘firmament’ traverses the depth-psychology corpus along two principal axes: cosmological-theological and psychological-symbolic. In the patristic tradition represented by John of Damascus and Augustine, the firmament functions as a literal cosmological boundary—the dividing membrane between upper and lower waters, debated as to its substance (watery, ethereal, fiery, or quintessential) yet consistently understood as the architectural pivot of Creation’s vertical order. Augustine, characteristically, transposes this cosmological structure into an interior grammar: the firmament becomes the ‘Book’ of God spread over the people, a metaphor for Scripture mediating between the eternal and the temporal. For Paracelsus, as rendered by Jung in ‘The Spirit in Man, Art, and Literature,’ the firmament is a second source of medical knowledge, an astrological macrocosm mirrored in the human body—‘heaven is man and man is heaven.’ This Paracelsian identification becomes Jung’s gateway to the firmament as an archetype of ordered totality, the horoscopic ‘thema’ through which the anima mundi maps itself onto individual constitution. Edinger draws on Ezekiel’s vision to locate the firmament as the threshold above which the divine throne appears, making it the liminal surface between human and transpersonal consciousness. Collectively, these voices position the firmament not merely as ancient cosmography but as a symbol of the psyche’s own organizing canopy—the structured boundary that both separates and mediates above and below.