The words "dream interpretation" were and still are indeed fraught with unpleasant, unscientific associations. They remind one of all sorts of childish, superstitious notions, which make up the thread and woof of dream books, read by none but the ignorant and the primitive. Besides those who sneer at dream study, because they have never looked into the subject, there are those who do not dare to face the facts revealed by dream study. Dreams tell us many an unpleasant biological truth about ourselves and only very free minds can thrive on such a diet. Self-deception is a plant which withers fast in the pellucid atmosphere of dream investigation. Freud's theories are anything but theoretical. He was moved by the fact that there always seemed to be a close connection between his patients' dreams and their mental abnormalities, to collect thousands of dreams and to compare them with the case histories in his possession.