There can be practically but one motive for theft, burglary, or robbery. It is, of course, conceivable that such crimes might be perpetrated for revenge—to deprive the victim of some highly prized possession. But in the main there is only one object—unlawful gain. So, too, blackmail, extortion, and kidnapping are all the products of the desire for “easy money.” _But, unquestionably, this is the reason for murder in comparatively few cases._ The usual motive for crimes against the person—assault, manslaughter, mayhem, murder, etc.—is the desire to punish, or be avenged upon another by inflicting personal pain upon him or by depriving him of his most valuable asset—life. And this desire for retaliation or revenge generally grows out of a recent humiliation received at the hands of the other person, a real or fancied wrong to oneself, a member of one’s family, or one’s property. But this was too easy an answer to my friend’s question. He could have got that much out of any elementary text-book on penology. He wanted and deserved more than that, and I set out to give it to him. My first inquiry was in the direction of original sources. I sought out the man in the district attorney’s office who had had the widest general experience and put the question to him. This was Mr. Charles C. Nott, Jr., who has been trying murder cases for nearly ten years. It so happened that he had kept a complete record of all of them and this he courteously placed at my disposal. The list contains sixty-two cases, and the defendants were of divers races. These homicides included seventeen committed in cold blood (about twenty-five per cent, an extraordinary percentage) from varying motives, as follows: One defendant (white) murdered his colored mistress simply to get rid of her; another killed out of revenge because the deceased had “licked” him several times before; another, having quarrelled with his friend over a glass of soda water, later on returned and precipitated a quarrel by striking him, in the course of which he killed him; another because the deceased had induced his wife to desert him; another lay in wait for his victim and killed him without the motive ever being ascertained; one man killed his brother to get a sum of money, and another because his brother would not give him money; another because he believed the deceased had betrayed the Armenian cause to the Turks; another because he wished to get the deceased out of the way in order to marry his wife; and another because deceased had knocked him down the day before. One man had killed a girl who had ridiculed him; and one a girl who had refused to marry him; another had killed his daughter because she could no longer live in the house with him; one, an informer, had been the victim of a Black Hand vendetta; and the last had poisoned his wife for the insurance money in order to go off with another woman. There were two cases of infanticide, one in which