I recently published a novel entitled The Con Man's Son, but I've just discovered a book which is apparently an important source of information on the type of criminal called a "confidence man."
First published in 1940, it offers a detailed study of con artists and their trade based on extensive interviews with practitioners.
It gives a historical survey of how simple street games like three-card monte developed into more elaborate "long cons" requiring establishment of a "store," a rented space set up to look like a betting parlor or stock brokerage.
There are also chapters on the crooks themselves, their social norms, the psychology of their victims, their cooperative relationships with law enforcement, and more.
Since the author was a linguist, the book makes use of the con-man's vocabulary ("rope a mark," "cop a heel," "steer against a store," etc.) and a glossary is provided.
I have no doubt The Big Con was a source for another book I have consulted, The Confidence Game. And anyone familiar with The Sting will recognize pages 31 through 52 as a description of the game operated by Henry Gondorff (Paul Newman) and Johnny Hooker (Robert Redford).
More and more I am convinced that when writing fiction, it's helps to know the facts.