important account that the psychopathologist's place in criminology is fully justified. In endeavoring to aid in the solution of the problem of criminology, the psychopathologist need not seek new methods of procedure but may safely rely upon those which have aided him in elucidating in a very large measure the problem of mental disease. For criminology is an integral part of psychopathology, crime is a type of abnormal conduct which expresses a failure of proper adjustment at the psychological level. It was not until the advent of the Kraepelinian School of psychiatry, with its intensive search for facts and the resultant more accurate delineation and classification of types of mental disorder, that we began to acquire real insight into psychopathology and were enabled to render more accurate prognoses. This more or less purely descriptive method of study is at present being followed by an intensive analysis of the facts thus gained as exemplified in the present psychoanalytic movement. It is conceded by all thoughtful observers that criminology will have to follow the same route on its way to final solution. The series of studies here presented reflect an effort in this direction. It is aimed to present a series of well-rounded-out case histories of criminal types as studied from the psychopathologist's viewpoint, and in one instance, at least, an attempt is made at an accurate and intensive psychological analysis of the biological forces which were at the bottom of a career of habitual stealing. No attempt is made at hard and fast formulations. Our knowledge concerning the criminal is still too meager to justify one in drawing dependable conclusions. But it is felt that this clinical material emphasizes sufficiently the necessity of the psychopathological mode of approach to the problem of criminology. For that matter, the excellent work being carried on by Dr. William Healy in connection with the Chicago Juvenile Court and by psychopathologists in a number of other cities attests that this need is being gradually recognized by society. One desires only to express the hope that the time is not far distant when our penal and reformatory institutions will likewise serve the purpose of clinics for the study of the delinquent, and that such clinical instruction will form part of the curriculum of at least every public prosecutor. I desire to express my indebtedness to Messrs. Lea and Febiger, the J. B. Lippincott Co., and to the editors of the American Journal of Insanity, and the Journal of the American Institute of Criminal Law and Criminology, for their kind permission to reprint some of the material herein presented. Before concluding this preface I desire to avail myself of this opportunity of expressing my sincere gratitude to Dr. William A. White, Superintendent of the Government Hospital for the Insane, for his kind and very stimulating advice and encouragement which made these studies possible.