For me, most entertaining was the guide to the types of scams and criminal enterprises operated at the turn of the century. Many are traditional - pickpockets, burglars and fraudsters - that would have been familiar in many cities and countries. But some reflect changing technologies - the railroad or the telegraph and the mail - that opened up new opportunities for the enterprising criminal.
In all of this Houdini presents himself as the honest broker, guiding the naive or innocent around the underworld that surrounds them in this newly urbanised and mobile society where strangers were not always what they seemed. Most of the criminals he exposes had been caught, though a few lucky individuals escaped with their ill-gotten gains. The right way to do wrong, as ever, is perhaps not to be detected.