Conversion occupies a pivotal position in the depth-psychological corpus, functioning simultaneously as a clinical category, a phenomenology of radical selfhood transformation, and a contested site where religion, psychology, and therapeutic theory intersect. William James establishes the foundational vocabulary in his Varieties of Religious Experience, distinguishing sudden from gradual conversion and attributing the former to the activity of the subliminal self — a reading that directly shaped Alcoholics Anonymous and its ambivalent, half-acknowledged debt to Jamesian psychology. Pargament elaborates conversion as a coping mechanism of the most thoroughgoing kind: not mere reconstruction of means nor simple revaluation of ends, but total transformation of significance, preceded by accumulated stress and the collapse of ordinary coping strategies, and consummated in surrender to the sacred. A counterpoint runs through the psychoanalytic tradition, where Freud and his successors use conversion in an entirely different register — the somatic conversion of inadmissible mental contents into bodily symptom — a usage Nijenhuis traces through the somatoform dissociation literature. Kurtz maps how A.A.’s founders navigated the word itself with notable discomfort, preferring euphemism over the evangelical directness of ‘conversion experience.’ Across all streams, tension persists between conversion as genuine psychological reorganization and conversion as defensive substitution, raising questions about authenticity, durability, and the differential outcomes for mental health.