Every once in a while-about a dozen times a week on the average--we get calls at Gambler's Book Shop for information on how cheats and hustlers operate. Most of those asking have that inquisitive sound in their voice, as if they're wondering how to a) protect themselves against cheats or b) learn how to turn the tables on cheats. Too, there are a few (we don't ask) who sound as if they want to "initiate a new career" as a cheat-but you never know. So, for those who have yet to ask, here are three titles and a short summary or review of each:

The Secret Science of Covert Inks by Samuel Rubin. This $14.95 paperbound (128 pages) is for the very inquisitive who want to research something more than the disappearing ink they experimented with in childhood. And it's surprising how many different types of covert inks exist. Published in 1987, it contains on key chapter for gamblers titled Gambler's Secret Inks. This chapter discusses and describes "marking inks" for playing cards, including the formulas and ingredients.

Another book, titled A Friendly Game? (The Textbook for Protecting Yourself From Being Cheated in the World's Best Card Game-Poker) by Bert Morris, has been available since 1996. This 106-page paperbound ($17.50) describes how cheaters mark cards using a variety of methods, including sand, wax, the human fingernail and daubs. Then there are the methods card sharks use in high-low split games to indicate whether to raise, pass or call, with samples of hand signals you might wish to be alert for in a game. The book goes on to describe card "mucking" techniques (the term applies to holding out a key card for use at some time later in a game); peeking at cards and how its done by dealers; dealing "seconds" and "bottoms" and one of the oldest forms of cheating-false shuffles.

A third book is a little bit of history mixed with how the old-timers cheated. What makes this book useful is the fact that techniques are often only refined rather than being innovative. The John Nevil Maskelyne classic titled Sharps and Flats (335 pages, paperbound, $8.95) was originally published in 1894. It spawned an entire generation of cheats.

Here you'll see detailed examples and explanation of how they marked cards a century or two ago; how reflectors were used to indicate what cards were being dealt; what "holdout" devices were and how they were used; how cards were manipulated and how partners applied collusion techniques. This is an extraordinary resource for anyone interested in the now defunct game of faro-the rules and layout are included. It is one of the best resources for isolating some of the earliest refinements by cheats for shooting craps and for cheating at roulette.