Oral erotism occupies a foundational position in the depth-psychological corpus, introduced by Freud in the Three Essays on the Theory of Sexuality (1905) as the earliest erotogenic organization of the infant, grounded in the mouth’s dual service to nutrition and libidinal pleasure, and elaborated with unmatched systematic force by Karl Abraham across multiple papers collected in his Selected Papers on Psychoanalysis (1927). Abraham’s contribution is decisive: he subdivides the oral stage into a sucking phase and an oral-sadistic (biting) phase, traces the constitutional inheritability of intensified oral erotism, and demonstrates its far-reaching consequences for character formation, including the disposition toward optimism, impatient dependence, and vampiric demands upon others. He also establishes the etiological link between strong oral fixation and manic-depressive illness, arguing that melancholic regression returns the libido to the oral-cannibalistic level. Lacan subsequently reframes the oral zone within a demand-desire topology, while Klein relocates the clinical weight onto the infant’s relation to the breast as good and bad object, emphasizing envy, splitting, and introjection over libidinal-zone mechanics. Winnicott’s concern with the mother’s handling quietly extends the oral domain into transitional-object theory. The central tension across these voices is whether oral erotism is best understood as a biological-constitutional given, a relational event, or a structural position within the subject’s economy of desire.