This edition of The Psychology of Man's Possible Evolution includes a lecture, not previously published, in which Ouspensky givers some details of the "School of the Fourth Way," with which he was connected, and an account of some of its fundamental principles, methods, and rules. The psychology Ouspensky sets forth in this introductory lectures has existed in one form or another for thousands of years and, unlike modern psychology, studies man from the point of view of what he may become. Once a man realizes how little control he has over his reactions to external circumstances and internal stimuli, he may wish to find a way to becomoe free of this mechanical way of living. Ouspensky describes how a man must work simultaneously on his knowledge and his being to find inner unity and why although his development depends on his own efforts, this is very difficult to achieve without guidance from a "School."