Freud and Klein were the pioneers and theoretical giants of the exploration of primordial mind. Jung was a contemporary of Freud and his contributions provide an interesting perspective. Because they tend to be more impressionistic than theoretically complex, and because he drifted outside the orbit of Freud's psychoanalytic movement, they have not received as much attention as they deserve. Bion's work expands upon a Kleinian base and Matte-Blanco was in¯uenced by Freud.