In this volume Dr. Sidis outlines his fundamental concepts of psychology, concepts and principles which have proven in his hands so rich and fruitful in their application to abnormal mental life.

         The psychic process is a biological process, and is, in its main characteristics, closely analogous to the life process. Both ontogenetically and phylogenetically the life process has a definite beginning and an end, neither being linked causally to antecedents and consequents. Purpose, or final causation is the attribute of the life process.

         This teleological aspect of the biological and psychic processes has its limitation. Sidis strongly emphasizes what he calls the chance aspects of life and mind. This concept is of fundamental importance in his psychology and emphasizes his divergence from the Freudian psychology which ascribes a meaning, a purpose and an adaptive value to every idea, to every fleeting thought, with the resulting highly artificial, far-fetched, often absurd interpretations of mental life. While it is true that teleology is of fundamental importance in evolutionary processes, this very purpose is achieved by a selective activity from an infinite number of spontaneous variations some of which are indifferent, have no adaptive values for the organism, and some are even injurious.

         The volume is devoted to a presentation of various psychological theories and principles, such as that of Reserve Energy, for instance, which the author has briefly presented in former works, but which are developed in great detail in the present volume.

         The "moment consciousness," a concept which Sidis first outlined briefly in his "Psychology of Suggestion," further in his "Multiple Personality" is fully developed in his present work. By the moment consciousness, regarded by him as the fundamental assumption of psychology, Sidis understands the synthetic unity which is the basis of all mental activity. Mental life is not simply a series of mental states, it is an individuality in which the psychic series occurs. The fleeting and ever changing psychic states are synthetized into an individuality as the physiological occurrences are synthetized into a biological organic unity, the organism. This synthetic unity, both the psychic individual and the psychic content, constitutes the moment consciousness. The moment consciousness is an organic unity very much like the functions of the organism, and cannot be broken into parts without at the same time destroying its very existence.

         Of special importance and significance are Sidis' studies of the various types of moments in the hierarchy of their complexity and stage of evolution, both ontogenetic and phylogenetic. These psychological studies of the various types or moments or of the various types of mental activities, arranged in their biological series from the lowest to the highest psychic functions of organic life, arc the most important in the volume and constitute one of the most comprehensive and significant contributions in the domain of psycho-biology, both normal and abnormal.

         These types of consciousness Sidis investigates closely. The studies are not only of importance in Normal Psychology, but are specially so in Abnormal Psychology. This is found in the recurrent aspect of functioning activity of the moment characteristic of the lower types of psychic life as well as of all regressive or retrogressive and degenerative forms of psycho-physiological dissociations present in psychopathic states. The aspect of recurrence of moment consciousness of the lower types is at the very foundation of Psychopathology and gives the underlying pathology of the clinical manifestations and of the symptomatology of psychopathic diseases. The scientific work of "The Foundations" strongly contrasts with the so-called "Psychoanalysis" and with "psychoanalytic" exegesis characteristic of the Austrian school of Freud and his disciples, a school that occupies itself with symbols, allegories, and myths.

         The reader is advised to give special attention to the second part of the volume.

         In the psycho-biological hierarchy, from the monocellular to the multicellular individualities, moments of consciousness differ in the complexity of their organization, from the simplest desultory moment to the most complex association of moments into groups and systems.

         The moment consciousness in its course of growth and development becomes extremely complex in its organization; it rapidly assimilates new material which it finds useful in its adaptation to the environment. The activity of the moment is either intensified or inhibited, according to the nature of the associated sets of groups of moments that have been set into activity. The organization of moments of the psychic individuality of various types carries within itself the regulative, inhibitive control. No special mechanisms are required for that purpose. Nor do we need to have recourse to Freudian repressions, suppressions, censors, and to all kinds of other mysterious agencies called in to explain with cunning ingenuity apparently inexplicable phenomena. Nor do we need to appeal to any mysterious will powers. Every psycho-biological system of groups carries within itself its own inhibitions which are just as requisite for normal activities as are the inhibitions in the organized system of physiological activities. In pathological states, or in abnormal mental conditions the inhibitions may either become accentuated, exaggerated, or on the other hand they may become completely removed. In case of dissociation the dissociated moment will react with its lull force and energy, because of the removal of the inhibitory control of associated sets of moments.

         In order to have a clear conception of the activity of the moment consciousness, Sidis utilizes the well established biological principles of cellular activity, namely of stimulus threshold and of inhibition. Not only is the intensity of the stimulus to be considered, but also the quality. Certain physiological systems, such as the various sense-organs will only respond to definite qualitative stimulations. Moreover, it is well recognized that the activity of one group of cells may have an inhibitory influence on the activity of another group. These physiological principles of stimulus threshold and inhibition are shown to apply to psychophysiological systems with their concomitant moments of consciousness.

         In connection with the application of the physiological factors of threshold stimulations and inhibition Sidis works out a principle of great importance, a principle also developed by Professor James at the same time with Sidis, but on other grounds, the principle of Reserve Energy.

         The evolution of mental life is from the simple to the complex. The increasing complexity of mental life, produced by the association of simple states into complex groups, brings about an inhibitory effect on the function of the components of the mental system. This inhibition, a concomitant of complexity of mental organization, is of inestimable value to the individual in his adaptations and adjustments to the environment, and plays no small role in the growth of civilization. The increase of the stimulus threshold of the moment, due to inhibition, produced by its association with other moments, prevents an undue exhaustion and permits the storing of energy requisite in critical moments as well as necessary to the progress of the individual and the race. Individual and social education aid in the formation and accumulation of reserve energy which makes all progress possible.

         With the development of mental life there is thus an ever greater storing of energy, and the ease with which this store of reserve energy may be accessible to the individual, to the race, or to society is an index of degree of civilization. The greater the store of reserve energy, and the greater the ease with which it can be reached to tide over critical moments as well as for other purposes necessary to the individual, race, and society, the higher the state of civilization may be regarded.

         Again the heightening of the stimulus threshold and consequent inhibition produced by natural selection and by education, individual and social, permits an ever greater accumulation of Reserve Energy, the condition of evolution and social progress.

         We can well realize that the outcome of the volume is of the utmost consequence not only from a theoretical standpoint, but also from a purely practical, medical, therapeutic standpoint, also specially from an educational and sociological point of view.