The professional criminal is a type little understood by the vast majority of people. Most people imagine him a type of man inherently and thoroughly vicious, with no saving grace in his character. The criminals I have known are not of this kind. Be it understood in writing of “professional” criminals that I mean the one known to the police as the professional man, the man who steals in some shape or another for a living, not the murderer or the ravisher, not the bigamist or the assaulter of women. These crimes are as foreign to the professional crook as they are to the average man.

The underworld can be divided into two principal classes, those of settled dispositions, preying in the locality in which they reside, and those whose methods take them[Pg 58] about the entire country and world. The former class is the less numerous. It is characterized by particularly petty acts. Working in the majority of cases under the protection of the police or some ward heeler, these men are seldom apprehended. In this class is found the petty “dip” (pickpocket), who makes the street cars and the markets his specialty. The confidence man who has seen better days, making his hangout in some second-class hotel, picking up a few pennies here and there with the connivance of the police, is another type. The receiver of stolen goods (a fence), with his little store as a blind, belongs to this group. Then there is the second-story man domiciled in some cheap lodging house, from whence he makes his nightly excursions into the realms of “chance.” In the city residing from year to year is also found the “stool” (informer). The police, knowing them to be incapable of big work, allow them to prey within certain restrictions for the information they bring to them. The stool never or seldom leaves the city. His chances of returning would be[Pg 59] slight indeed if the f............