Since the date of the last edition (1918) the centre of interest in psycho-analytic research has been shifted from the nature of repressed impulses to the study of the ego itself which stands in contrast with them. It is certain, however, that the only sound way of approaching this more abstruse side of the subject still lies through a patient investigation of the transference manifestations of the unconscious-ie, the repressed allo-erotic impulses which manifest themselves so extensively in dreams and in psycho-neuroses. These fields of inquiry, the most accessible to direct clinical observation, will doubtless always constitute the necessary preliminary to any form of psycho-analytic study.

In the same period the most important event in what may be called the psycho-analytical movement has been the resumption of scientific intercourse among the workers in different countries who were separated by the War. The International Psycho-Analytical Association was the first body to hold an international scientific congress after the War. Among the fruits of this reunion may be signalled the initiation of the International Psycho-Analytical Press, with its International Journal of Psycho-Analysis (an official organ of the Association) and its library of monographs. The increased diffusion of vii