Randall Garrett

“ Walsh was a big-time gambler, with ulcers and high blood pressure and ten million in the bank. Rafferty was straight middle-time, a man who genuinely enjoyed his chancy profession. And Walsh had said, "Why don't you play something I like to play? All the time poker, poker, poker. Why don't you switch to something else."
"I like poker," Rafferty said. "I win at poker. Why switch?"
Walsh seemed to stiffen. "Let's have a little game of planet-faro, Rafferty. Just you and me. I'm tired of all this poker." ”

“ That was the secret of poker: never to tip off an opponent to anything. Steel was good, but Steel kept giving himself away.
Like now, for instance. Perhaps the shill didn't know it, but his right eyebrow was twitching faintly. So far, every time Steel had bluffed a weak hand, that eyebrow had twitched.
Well, now Rafferty had him. He had a full house; it was going to take a bunch of fancy cards to top it. And Steel was almost certainly bluffing. ”

“ But slowly Rafferty began to fathom the way his opponent's mind worked. And slowly, as his genius for the game asserted itself, Rafferty began to win.
By 2100 his pile of chips totalled near fifty thousand. It was enough to pay off Walsh and still come out with a comfortable profit for the evening's work—but Rafferty didn't want to quit. He didn't play the game that way.
He decided to go for a killing. He had Steel figured, now and he could take the house for a fortune.
Nursing three jacks and a pair of fours, he pushed the betting higher and higher. Steel kept right with him. ”