The importance of fantasy in the course of normal development, and in the causation of neurosis, has been emphasized from the earliest days of psychoanalytic psychology. Some workers have attempted to define different types of fantasies, their development and course, others to determine its nature as a form of primitive thinking. All who work in this field agree that there are certain universal fantasies which enter into and affect normal mental development. Often the overt form of a fantasy has behind it a latent form (to borrow the terminology of dream psychology), which can be discovered only by analyzing the associations of the person who has the fantasy.