In these lectures I have also endeavored (Lectures XIV-XVI) to develop the phenomena of the emotional innate dispositions which I conceive play one of the most fundamental parts in human personality and in determining mental and physiological behavior. Experimental methods and the well-known clinical methods of investigation have been employed by me as far as possible. The data made use of have been derived for the most part from my own observations, though confirmatory observations of others have not been neglected. Although a large number and variety of subjects or cases have been studied, as they have presented themselves in private and hospital practice, the data have been to a large extent sought in intensive studies, on particular subjects, carried on in some cases over a period of many years. These subjects, because of the ease with which subconscious and emotional phenomena were either spontaneously manifested or could be experimentally evoked, were particularly suitable for such studies and fruitful in results. It is by such intensive studies on special subjects, rather than by casual observation of many cases, that I believe the deepest insight into mental processes and mechanisms can be obtained. In conclusion I wish to express my great obligation to Mrs. William G. Bean for the great assistance she has rendered in many ways in the preparation of this volume. Not the least has been the transcription and typing of my manuscript, for the most part written in a quasi shorthand, reading the printer’s proofs, and much other assistance in the preparation of the text for the press. For this her practical and unusually extensive acquaintance with the phenomena has been of great value. I am also indebted to Mr. Lydiard Horton for kindly reading the proofs and for many helpful suggestions in clarifying the arrangement of the text—a most difficult task considering the colloquial form of the original lectures. Boston. 458 Beacon Street. PREFACE TO SECOND EDITION The favorable reception which was given to the first edition of this work has tempted me in preparing a new edition at the request of the publishers to incorporate four additional chapters dealing with the general principles underlying the structure and dynamic elements of human personality (Lecture XVII) and a study of a special problem in personality in which these principles are involved, namely, the psychogenesis of multiple personality as illustrated by a study of the case known as B. C. A.[3] (Lectures XVIII-XX.) The latter study was omitted (with other lectures) from the first edition in order to limit the number of subjects treated and the size of the volume.