The term ‘axis’ traverses the depth-psychology corpus along several interlocking registers, each designating a dynamic polarity rather than a static line. The most clinically influential usage is Edward Edinger’s formulation of the ego-Self axis, a concept credited to Neumann, which names the vital structural and energetic link between the conscious ego and its transpersonal ground. Hollis extends this axial thinking into a developmental schema, identifying four successive axes — parent-child, ego-world, ego-Self, and Self-Cosmos — that organize the successive identities of a human life. Neumann, working at the archetypal level, deploys the axis as the path of movement within the Great Mother schema, representing the trajectory of ego-consciousness through stages of containment, transformation, and spiritual transcendence. In the astrological literature, Greene and Rudhyar treat the nodal axis as the crystallization point of the Sun-Moon coniunctio and of the individual’s destiny understood as the tension between ego-will and solar Self. McGilchrist, approaching from neuroscience, maps three spatial axes of opponent-processor pairs in the brain — vertical, lateral, and a third — showing that axial organization is not merely metaphorical but structurally constitutive of mind. What unites these diverse registers is the axis as the organizing principle of a polarity held in dynamic tension: it is not separation but the living between-space that makes psychic differentiation and developmental movement possible.