Professor Lazursky's² book comes out in a new edition at a time when both Russian psychological science and the teaching of the psychological disciplines in the higher educational institutions are suffering an acute crisis. On the one hand, through the methods of exact natural science the successes of physiological thought penetrated into the most complex and difficult areas of higher nervous activity. On the other hand, there was an ever growing opposition to the traditional systems of empirical psychology within the psychological science itself. These factors caused and determined this crisis. To this was added the fully inevitable and natural desire, common to almost the entire contemporary Russian cultural front, to reconsider the foundations and principles of psychology in light of dialectical materialism, to connect the scientific-investigative, theoretical elaboration and the teaching of this science with more general and fundamental premises of a philosophical character.