In accordance with the purpose of this series to extend knowledge of the important discoveries affecting individual and social welfare that have been made during recent years through psychological investigation, the present volume surveys the principles and results of scientific dream-analysis along the lines first formulated by Doctor Sigmund Freud, of Vienna. Though Freud's views are by no means those of all medical psychologists, and have indeed been vigorously criticized by not a few, there is general agreement that he has rendered a real service to both psychology and medicine by his demonstration of the practical value of dream-study. Certainly no one has more thoroughly investigated the mechanism of dreams, and all future explorers of this phase of the mental life of man will owe much to his pioneering efforts.

To be sure, it must also be said that most medical psychologists at present believe Freud has erred in attempting to reduce all dreams to a single formula. Certainly, however, his formula holds good in a surprisingly large number of instances, as the reader will discover. And, apart from the question of its invariability, there can be no denying the soundness of the fundamental principle on which all Freudian dream-analysis rests - the principle, namely, that every dream, no matter how trivial, fantastic, or meaningless it may seem, has a definite meaning, and a meaning that sometimes is of great significance to the dreamer.

Consequently a series like the present one would be incomplete without a detailed survey of dreams from the Freudian standpoint. For this task Doctor Coriat is well qualified. Few American physicians are as familiar as he with the doctrines and methods of Freud, or have applied them so consistently in the treatment of nervous and mental disease. He has had an extensive clinical experience, having been for some years connected with the Worcester State Hospital for the Insane, and afterward with the Boston City Hospital, with which he still is associated. He is a member of many scientific, medical, and learned societies in America and Europe, is one of the editors of the Journal of Abnormal Psychology, and, besides having written many technical papers on nervous and mental disorders, is the author of a valuable textbook on "Abnormal Psychology." In that work, as in this, Doctor Coriat draws on his own experiences to illustrate and reinforce the more important points in his exposition.