The theory of repression is the main pillar upon which rests the edifice of psychoanalysis. It is really the most essential part of it, and is itself nothing other than the theoretical expression of an experience which can be repeated at pleasure whenever one analyzes a neurotic patient without the aid of hypnosis. One is then confronted with a resistance which opposes the analytic work by causing a failure of memory in order to block it. This resistance had to be covered by the use of hypnosis; hence the history of psychoanalysis proper only starts technically with the rejection of hypnosis. The theoretical value of the fact that this resistance is connected with an amnesia leads unavoidably to that conception of the unconscious psychic activities which is peculiar to psychoanalysis, and distinguishes it markedly from the philosophical speculations about the unconscious. It may, therefore, be said that the psychoanalytic theory endeavors to explain two experiences, which result in a striking and unexpected manner during the attempt to trace back the morbid symptoms of a neurotic to their source in his life-history; viz., the facts of transference and of resistance. Every investigation which recognizes these two facts and makes them the starting points of its work may call itself psychoanalysis, even if it lead to other results than my own. But whoever takes up other sides of the problem and deviates from these two assumptions will hardly escape the charge of interfering with the rights of ownership through attempted imitation, if he insist upon calling himself a psychoanalyst.