Within the depth-psychology library, ‘Otto’ functions as a multi-referential node, pointing primarily to three distinct figures whose contributions intersect at the borderlands of religion, myth, and the unconscious. Rudolf Otto (1869–1937), author of Das Heilige (1917), provides the foundational phenomenological account of the numinous — the experience of the mysterium tremendum et fascinans — which Eliade explicates as the defining text for analyzing irrational religious experience, and which Tarnas situates within the Uranus-Neptune opposition as part of a broader wave that also produced James’s Varieties and shaped Jung’s integration of numinosity into analytical psychology. Walter F. Otto (1874–1958), the classicist-philologist, is the second major figure: his Dionysus: Myth and Cult and Die Götter Griechenlands are treated by Kerényi and his translator Palmer as a theogonic recovery of Greek religion that transcends mere scholarship and demands a poetic-apocalyptic style. Kerényi was directly Otto’s student, and the Nietzschean inheritance is explicit. The third figure is Otto Rank, the psychoanalytic theorist of will, birth trauma, and artistic creativity, cited by Yalom as the originator of will-therapy within the clinical tradition and present in Freud’s own prefaces as a trusted collaborator. These three Ottos converge in the corpus around questions of sacred encounter, mythic authenticity, and the dynamics of individuation.