Castration anxiety occupies a structurally central, though fiercely contested, position across the depth-psychology corpus. In its classical Freudian formulation, it designates the boy’s dread of penile loss as punishment for oedipal desire — a fear Freud ultimately elevated to the generic source of all anxiety, subsuming prior separation experiences and templating neurotic inhibition, phobia, and symptom-formation throughout adult life. Karl Abraham extends the concept with methodical precision, tracing its clinical reverberations in fetishism, ejaculatio praecox, scopophilic disturbance, female penis envy, and the entire edifice of the female castration complex — documenting how the fear of genital loss, in both its active and passive forms, generates impotence, frigidity, perversion, and conversion symptomatology. Melanie Klein displaces the temporal origin radically earlier, situating castration fear within a matrix of pre-oedipal persecutory and depressive anxieties, insisting that it cannot be understood apart from oral-sadistic impulses and the paranoid-schizoid position. Yalom’s existential critique is the most searching: he argues that what passes clinically for castration anxiety is frequently a disguised, ‘processed’ form of death anxiety — that Freud’s privileging of castration obscured the more fundamental terror of annihilation visible in the very case material from which he drew his conclusions. Otto Rank’s birth-trauma thesis represents a parallel challenge, locating primal anxiety even earlier than the phallic stage. Together these voices reveal castration anxiety as both a precise clinical construct and a contested placeholder for the question of what human beings most fundamentally fear.