A DETECTIVE, according to the dictionaries, is one “whose occupation it is to discover matters as to which information is desired, particularly wrong-doers, and to obtain evidence to be used against them.” A private detective, by the same authority, is one “engaged unofficially in obtaining secret information for or guarding the private interests of those who employ him.” The definition emphasizes the official character of detectives in general as contrasted with those whose services may be enlisted for hire by the individual citizen, but the distinction is of little importance, since it is based arbitrarily upon the character of the employer (whether the State or a private client) instead of upon the nature of the employment itself, which is the only thing which is likely to interest us about detectives at all. The sanctified tradition that a detective was an agile person with a variety of side-whiskers no longer obtains even in light literature, and the most imaginative of us is frankly aware of the fact that a detective is just a common man earning (or pretending to earn) a common living by common and obvious means. Yet in spite of ourselves we are accustomed to attribute superhuman acuteness and a lightning-like rapidity of intellect to this vague and romantic class of fellow-citizens. The ordinary work of a detective, however, requires neither of these qualities. Honesty and obedience are his chief requirements, and if he have intelligence as well, so much the better, provided it be of the variety known as horse sense. A genuine candidate for the job of Sherlock Holmes would find little competition. In the first place, the usual work of a detective does not demand any extraordinary powers of deduction at all. Leaving out of consideration those who are merely private policemen (often in uniform), and principally engaged in patrolling residential streets, preserving order at fairs, race-tracks, and political meetings, or in breaking strikes and preventing riots, the largest part of the work for which detectives are employed is not in the detection of crime and criminals, but in simply watching people, following them, and reporting as accurately as possible their movements. These functions are known in the vernacular as spotting, locating, and trailing. It requires patience, some powers of observation, and occasionally a little ingenuity. The real detective under such circumstances is the man to whom they hand in their reports. Yet much of the most dramatic and valuable work that is done involves no acuteness at all, but simply a willingness to act as a spy and to brave the dangers of being found out. There is nothing more thrilling in the pages of modern history than the story of the man (James McPartland) who uncovered the conspiracies of the Molly McGuires. But the work of this man was that of a spy pure and simple.