The purpose of this essay in descriptive psychology is to provide a survey of a comprehensive aspect of human psychic endowment. The very definition of psychology as the science of consciousness has tended to focus attention upon conditions of high introspective lucidity, and, by implication, to look upon areas from which such illumination is withdrawn, as quite too obscurely lighted for profitable examination. Thus casually visited, and with no vital share in the psychologist's concerns, the abode of the subconscious has drifted into the service of a lumberroom, in which to deposit what finds no place in the mind's active economies. As a statement of its natural import, its comprehensive scope in the familiar fields of normal life and in the perplexing mazes of the abnormal, I have undertaken a systematic exposition of subconscious functioning. It requires a volume to convey a proper conception of the intimacy of such participation in the normal trend of the mind's affairs; and, with similarly motived excursions into the abnormal field, of the instructive issues that ensue when its role is imperfectly played. There is, indeed, no corner of the mental establishment that can well remain unvisited, if one would appreciate the pervasiveness of this influence in the household. It is for such a tour of inspection, undertaken with systematic purpose, that the book offers its services as a modest cicerone. (PsycINFO Database Record (c) 2004 APA, all rights reserved).