Small as this volume is, it has required many communications with the old world, and the author's thanks are due to many students engaged upon the study of this science in England and in the United States, and who have rendered him valuable assistance. Also, the assistance of many kind friends in New Zealand is gratefully acknowledged, and particularly that of Mr Alfred Grant, without whose aid the preparation of these sheets for the press would have been an almost impossible task. Chapter II. THE CRIMINAL. The popular mind draws little or no distinction between criminals. In it there exists the idea of a criminal caste, all the members of which are prepared to commit any and every act of a criminal nature. In the popular mind, although it is just a question whether a man is bad enough to commit the greater crimes, yet thieves, violators, swindlers, forgers and murderers are all assumed to fall into the same category. In one sense they do, that is, that they are all anti-social beings, or rather they all possess certain anti-social qualities; but as soon as we proceed further we find that there exists a very great distinction in criminals. Criminals are first classified according to the motive of their crime. This classication ranges them under five different headings, the political criminal, the occasional criminal, the criminal of passion, the instinctive criminal, and the habitual criminal or recidivist. Again they are classified, according to the nature of their crime, into thieves, robbers, violators, assassins, murderers, swindlers, etc. These again are sub-classified, e.g., thieves are classified as housebreakers, those who rob with violence, those who use weapons, those who rob from the person, and those who break safes. Murderers may also be classified according to the nature of their murderous instinct, illustrated by the instrument of destruction that they employ, whether it be the knife, firearms, poisons or other means, and again a classification exists between those who commit murder themselves and those who employ agents. All these classifications are entirely different, and although some criminals may range under more than one heading, yet it is generally the case that a criminal adopts both a certain form of crime and also a particular method for carrying it into execution. =The Political Criminal.=--This man's offence is not against morality but against the governmental institutions of the country. He holds advanced ideas upon matters of government and upon the constitution of society, and in his attempt to propagate these he becomes a political criminal. The political criminal, as distinguished from all other criminals, never commits violence, his morals may even approach perfection; but he holds "ideas," ideas which are not acceptable to the government under which he lives.