THE new psychology of dreams, as elaborated by Freud, represents one of the greatest advances ever made in our knowledge pf the human mind and of human motives. For abnormal psychology, dream-analysis can be compared only in importance with the discovery of the origin of species and of the factors of organic evolution in the field of biology. The analysis of dreams is not only of great theoretical value in the understanding of the unconscious but has its practical side as well, in giving medicine the most potent instrument which it has ever possessed in the treatment of certain functional nervous disturbances.This volume is written along purely psycho-analytic lines, and every dream therein has been personally analyzed by the author. Its aim is to give the general reader an outline of the meaning of dreams as elaborated by the psycho-analytic school, with its applications to medical science, in particular to that method of psychotherapy known as psycho-analysis. Because of the great difficulties inherent in the subject of dream-analysis, only the basic principles have been given, the details being left for the special treatises and journals on the subject.ISADOR H. CORIAT.Boston, February, 1915.

ABNORMAL psychology, or the study of abnormal mental phenomena, is one of the late developments of scientific medicine. It is not a mere fad, as some of its critics would attempt to make us believe, neither has it sprung up like a mushroom, within a single night. Abnormal psychology is the outcome of the work of small groups of investigators in France, Germany, and America, within the last twenty- five years. Beginning with a study of the phenomena of hypnosis, these researches gradually developed into a series of brilliant psychological discoveries. The most important of these is the principle of dissociation or of N splitting of the mind. In a general way we speak of these matters as the theory of the subconscious. This theory has not only thrown an immense amount of light on the nature of human personality, but other peculiar phenomena, such as losses of memory or amnesia, automatic writing, crystal gazing, and such diseases as neurasthenia, hysteria, psychasthenia, have been stripped of the mystery which surrounded them for centuries. These phenomena, even more than the modern investigations on the ultimate nature of matter, form the "fairyland of science." Apart from any scientific knowledge, the general reader has a certain interest in these problems, either from curiosity or the light they shed upon human personality or perhaps from the mystery which seems to surround them.Abnormal psychology has also its practical aspects. Its discoveries have made possible the psychic treatment of certain functional nervous disorders. Technically, this is known as psychotherapeutics. The interpretation of these functional states is based on the principle of the dissociation of consciousness. But psychotherapeutics would be in a very chaotic condition and barren of results, were it not for abnormal psychology, for a scientific psychotherapeutics must be based upon a sound psychopathology.