Infancy occupies a privileged and contested site in the depth-psychology corpus, functioning simultaneously as a developmental epoch, a theoretical object, and a template for understanding adult psychopathology. Winnicott stakes out the most elaborated position: infancy is the crucible within which ego-continuity is either secured through good-enough maternal holding or fractured through impingements that produce annihilation anxiety and proto-psychotic states. For Klein, infancy is the theater of the earliest object relations, persecutory and depressive positions, and the constitutional operation of the life and death instincts from birth onwards — a position that required her to read the infant’s rage, feeding disturbances, and fleeting sadness as emotionally meaningful from the first weeks of life. Bowlby and attachment theorists reconfigure infancy around proximity-seeking, separation protest, and the progressive construction of representational models of the attachment figure. Schore’s neurobiological synthesis situates infancy at the intersection of caregiver affect-regulation and the experience-dependent maturation of the orbitofrontal cortex, bridging psychoanalytic theory and developmental neuroscience. Post-Jungian debate, particularly between Fordham and Neumann as surveyed by Samuels, concerns whether the infant is best understood as a separate individuating agent from conception or as embedded in archetypal participation mystique. Across all these positions the stakes are the same: infancy is not merely a biographical beginning but the generative matrix of self-structure, relational capacity, and vulnerability to breakdown.