THE present work was the first really objective Criminal Psychology which dealt with the mental states of judges, experts, jury, witnesses, etc., as well as with the mental states of criminals. And a study of the former is just as needful as a study of the latter. The need has fortunately since been recognized and several studies of special topics treated in this book--e. g. depositions of witnesses, perception, the pathoformic lie, superstition, probability, sensory illusions, inference, sexual differences, etc.--have become the subjects of a considerable literature, referred to in our second edition.
I agreed with much pleasure to the proposition of the American Institute of Criminal Law and Criminology to have the book translated. I am proud of the opportunity to address Americans and Englishmen in their language. We of the German countries recognize the intellectual achievements of America and are well aware how much Americans can teach us.
I can only hope that the translation will justify itself by its usefulness to the legal profession. HANS GROSS.
THE present version of Gross's Kriminal Psychologie differs from the original in the fact that many references not of general psychological or criminological interest or not readily accessible to English readers have been eliminated, and in some instances more accessible ones have been inserted. Prof. Gross's erudition is so stupendous that it reaches far out into texts where no ordinary reader would be able or willing to follow him, and the book suffers no loss from the excision. In other places it was necessary to omit or to condense passages. Wherever this is done attention is called to it in the notes. The chief omission is a portion of the section on dialects. Otherwise the translation is practically literal. Additional bibliography of psychological and criminological works likely to be generally helpful has been appended.
OF all disciplines necessary to the criminal justice in addition to the knowledge of law, the most important are those derived from psychology. For such sciences teach him to know the type of man it is his business to deal with. Now psychological sciences appear in various forms. There is a native psychology, a keenness of vision given in the march of experience, to a few fortunate persons, who see rightly without having learned the laws which determine the course of events, or without being even conscious of them. Of this native psychological power many men show traces, but very few indeed are possessed of as much as criminalists intrinsically require. In the colleges and pre-professional schools we jurists may acquire a little scientific psychology as a ``philosophical propaedeutic,'' but we all know how insufficient it is and how little of it endures in the business of life. And we had rather not reckon up the number of criminalists who, seeing this insufficiency, pursue serious psychological investigations.
One especial psychological discipline which was apparently created for our sake is the psychology of law, the development of which, in Germany, Volkmar recounts. This science afterward developed, through the instrumentality of Metzger and Platner, as criminal psychology. From the medical point of view especially, Choulant's collection of the latter's, ``Quaestiones,'' is still valuable. Criminal psychology was developed further by Hoffbauer, Grohmann,
 W. Volkmann v. Volkmar: Lehrbuch der Psychologie (2 vols.). C
 J. Metzger: ``Gerichtlich-medizinische Abhandhingen.'' K