Identification occupies a contested and multiply-determined position within the depth-psychology corpus. At its most foundational, the term designates the psychic process by which the ego assimilates itself to another person, function, or object—a usage Freud crystallized in ‘The Ego and the Id’ (1923), where identification with the parent structures the resolution of the Oedipus complex and consolidates character. Jung, in ‘Psychological Types’ (1921), extends the concept diagnostically: identification with one’s most differentiated function produces a secondary persona-character and drives the original individuality into the unconscious, making it a necessary but perilous transitional stage toward individuation. Neumann sharpens the ethical dimension, arguing that ego-identification with the persona and collective values generates dangerous inflation and shadow repression. Klein’s introduction of ‘projective identification’ in 1946 marks a paradigm shift: identification becomes not merely intrapsychic but interpersonal—a mechanism by which split-off contents are evacuated into another and that other is unconsciously coerced to embody them. Ogden, Flores, Yalom, and Sedgwick carry this object-relational account into group and clinical settings, treating projective identification as simultaneously a primitive defense, a communication, and an intersubjective event. Welwood, working at the Buddhist-psychotherapy interface, frames prereflective identification as the root condition of ordinary unconscious suffering. Ricoeur, approaching from philosophical hermeneutics, uses the term more narrowly as the logical operation of re-identifying the same entity across time—the cognitive counterpart of numerical identity. Across these registers, identification names the mechanism by which self-boundaries are established, dissolved, and renegotiated.