The most essential requirement that the analytic process demands of the patient is the split of his ego into an observing part and an experiencing part. The latter regresses to archaic infantile levels while the former maintains a sharp level of maturity and sophistication. The conditions that favor regression are the basic rules—abstinence, the analyst's anonymity, and the recumbent position. The regression does not involve the whole psychic apparatus. Some functions regress markedly while others remain sharply in contact with reality. The anlage of the regressive relationship is the early mother-child relationship. The optimal degree of regression is different for each individual. In the countertransference there is also a regression, and 'complementary identification' is the best instrument for understanding the regressive object relations of the patient. Regression is also utilized by the patient for defensive purposes. In the terminal phase the balance must favor autonomous functioning over regression.