The development of the transference concept is described and studied from structural genetic, dynamic and adaptive points of view. A sketch is given of the development of a transference neurosis during treatment, and of the difference between transference phenomena and transference neurosis. A number of examples from practice are given, also in connection with the occurring repetition compulsion. In the discussion of the counter transference concept a distinction is made between the so-called classic approach and the totalistic approach of this concept. The author studies the possible interference of the countertransference during treatment. If the analyst can withdraw from his trial identification with his patient no interference will occur. Sudden countertransference phenomena may be eliminated by self-analysis. Chronic countertransference phenomena can only be solved by re-analysis. Examples from practice are given and the fact is demonstrated that analyst and analysant are not only tranference-countertransference objects for each other, but also real objects. Attention is paid to the old and the new concept of acting-out. Examples from practice are given of acting-out during and outside the analytic sessions.