The head-quarters man has no time nor inclination to follow the sporting duchess and the fictitious earl who accompanies her in their picturesque wanderings around the world. He is busy inside the confines of his own country. Parents or children may disappear, but the mere seeking of oblivion on their part is no crime and does not concern him except by special dispensation on the part of his superiors. Divorced couples may steal their own children back and forward, royalties may inadvertently involve themselves with undesirables, governmental information exude from State portals in a peculiar manner, business secrets pass into the hands of rivals, race-horses develop strange and untimely diseases, husbands take long and mysterious trips from home—a thousand exciting and worrying things may happen to the astonishment, distress, or intense interest of nations, governments, political parties, or private individuals, which from their very nature are outside the purview of the regular police. Here, then, is the field of the secret agent or private detective, and here, forsooth, is where the detective of genuine deductive powers and the polished address of the so-called “man of the world” is required. There are two classes of cases where a private detective must needs be used, if indeed any professional assistance is to be called in: first, where the person whose identity is sought to be discovered or whose activities are sought to be terminated is not a criminal or has committed no crime, and second, where, though a crime has been committed, the injured parties cannot afford to undertake a public prosecution. For example, if you are receiving anonymous letters, the writer of which accuses you of all sorts of unpleasant things, you would, of course, much prefer to find out who it is and stop him quietly than to turn over the correspondence to the police and let the writer’s attorneys publicly cross-examine you at his trial as to your past career. Even if a diamond necklace is stolen from a family living on Fifth Avenue, there is more than an even chance that the owner will prefer to conceal her loss rather than to have her picture in the morning paper. Yet she will wish to find the necklace if she can. When the matter has no criminal side at all, the police cannot be availed of, although we sometimes read that the officers of the local precinct have spent many hours in trying to locate Mrs. So-and-So’s lost Pomeranian, or in performing other functions of an essentially private nature—most generously. But if, for example, your daughter is made the recipient, almost daily, of anonymous gifts of jewelry which arrive by mail, express, or messenger, and you are anxious to discover the identity of her admirer and return them, you will probably wish to engage outside assistance.