Dr. Bonger sees clearly that the concept of crime is a social and not a biological one. It is the social value or harmfulness of acts or conduct that is involved in the concept and if we use terms that have a predominantly biological connotation such as “normal” or “abnormal”, we must be careful to distinguish that use as referring to a social standard or we will be in danger of a confusion of thought. That some of the acts which society has classed as crimes may be deemed pathological is incidental; it is not on this account that they are termed crimes but because they are socially detrimental. That some of the individuals who have committed crimes may be called “abnormal” is incidental; it is not because of this that they are classified as criminals. That the economic factor has a large influence in connection with that kind of conduct the social significance of which stamps it as criminal the author abundantly shows. The extent to which this is the case and the extent to which the economic conditions involved are inherent in our present social organization are matters on which there will be difference of opinion with the author. Dr. Bonger’s expressed belief that his main positions will be received without sympathy in this country we venture to think will not prove to be well founded. On the contrary so clearly has he set them forth and so well has he supported them that they can hardly fail of appreciation. If this work serves to some extent as a corrective to a too prevalent tendency toward a confusion of thought between biological and social concepts and standards in the study of human conduct—and especially that kind of conduct which we have deemed so socially detrimental as to brand as crime—its inclusion in this series will be amply justified. Warren, Pa. February 26, 1916. INTRODUCTION TO THIS VOLUME. By Frank H. Norcross. [1] Dr. Bonger’s work—“Criminality and Economic Conditions”—will arrest the attention of students of criminology, sociology and kindred subjects. In it, also, the political economist may delve with profit.