The oral stage occupies a foundational position in the depth-psychological corpus, yet its treatment is anything but uniform. Karl Abraham stands as the essential systematizer of this concept: working within and extending Freud’s libido theory, he mapped the oral stage’s two sub-phases — the sucking phase and the oral-sadistic biting phase — and traced their lasting imprints on character formation, object relations, and the psychopathology of melancholia and mania. For Abraham, fixation or regression to the oral stage yielded recognizable character constellations: an insatiable demandingness, clinging dependency, and an ambivalence toward objects that mirrored the cannibalistic wish to incorporate and destroy. Melanie Klein radicalized this inheritance, relocating much of the drama of the oral stage to the earliest weeks of life. Her work made oral-sadistic impulses — directed against the mother’s breast — the seedbed of primary anxiety, splitting, and the paranoid-schizoid position, thus giving the oral stage a structural weight it had not possessed even in Abraham. What distinguishes the corpus as a whole is this sustained tension between the metapsychological (libido regression, fixation points) and the object-relational (the breast as primal good or persecutory object). The oral stage, in this literature, is not merely an early phase of development; it is the template upon which all subsequent relations to nourishment, dependency, envy, and trust are patterned.