The key principle is what he calls "non-self-weighting strategies". This means getting your money on when chances are in your favour (e.g. counting cards at blackjack). Whereas self-weighting strategies mean always making the same play for similar-sized bets.
Here is an example from poker. Suppose you are playing draw, jacks or better to open, played with a joker that may count as an ace or be used to complete straights and flushes. You are dealt a pair of aces. How should you play the hand? Mason says the typical player plays his hand in a straightforward manner. If no one has yet opened, he will open; if someone has opened, he will call. This is a self-weighting (and self-defeating) strategy.
By contrast, the expert player will open most of the time in early position, but not all the time; if someone else has opened, he will call most of the time, but not all the time. If his opponent has opened very late, he will raise. If a tight player opens early, the expert knows he is up against a quality hand. Elementary, my dear Malmuth, you may say. But note that it doesn't matter what game it is. The expert, following a non- self-weighting strategy, will consistently take home the money.
Note that having the best of it doesn't necessarily mean winning. There will be many fluctuations along the way. Successful gamblers, says Malmuth, are statisticians, not mathematicians.
Order `Gambling Theory' from High Stakes, 21 Great Ormond Street, London WC1N 3JB (0171-430 1021), price pounds 29.95