Various psychoanalytic theories about the emotional and social development of normal infants are current. Each is associated primarily with the individual who has advanced it. Limits are set to the usefulness of the theories by their efforts to comprehend overly broad areas of psychic growth, by their speculative quality, and by their reliance on insufficient data. Progress toward understanding the psychic structure of infants depends upon the coordination of psychoanalytic observations and theory with the studies of infant behaviors being made by developmental and experimental psychologists.