Primary envy occupies a pivotal and contested position within the depth-psychology corpus, standing as Melanie Klein’s most consequential late theoretical contribution — introduced systematically in 1957 — and generating reverberations across object-relations theory, clinical technique, and developmental metapsychology. Klein locates primary envy at the very origin of psychic life: an innate, constitutionally variable destructive impulse directed against the feeding breast, distinct in both temporality and structure from the jealousy that follows in the Oedipal constellation. It is primary because it precedes triangulation, because it attacks the good object precisely on account of its goodness, and because it operates before the ego possesses sufficient integration to metabolize or deflect it. Bion, engaging Klein’s formulation, amplifies its clinical weight by connecting the infant’s primary aggression and envy to attacks on linking — the catastrophic disruption of the very capacity to form mental connections. Within the treatment situation, Klein traces how primary envy resurfaces as negative therapeutic reaction, as the patient’s inability to receive interpretation gratefully, and as repeated devaluation of the analyst. The constitutional dimension — the degree to which envy is innate rather than environmentally induced — introduces irreducible tension with therapeutic optimism. Edinger and the Jungian tradition reframe envy more ambivalently, as a signal of psychic deficit and hunger rather than pure destructiveness. The Kleinian literature insists, however, that primary envy is the prototype and engine of all later spoiling, and that its analysis is indispensable to any fundamental therapeutic change.