To a casual bettor at Hollywood Greyhound Track, the races may look like utter chaos: the starting box opens and eight dogs go hurtling into the first turn, bumping and sometimes knocking each other on their rear ends.

To John Uller, these events once looked chaotic, too. But he has since joined the small fraternity of men who earn their living by better on dog races and he recognizes that these 31-second mad dashes are governed by order, reason and logic.

Uller grew up in Miami Beach and started going to the local dog tracks when he had to use a fake ID to get in the gate. "I'd go every night and try to handicap from the program and keep blowing my paycheck. Finally, I said, 'I'm sick of this.' Like everyone else, I had been watching races every night and not comprehending what I was seeing. I realized that if you have to look in the book (the program), you're not going to win."

After paying his tuition, Uller learned that dog racing is almost strictly a visual game, and that intelligent bettors all form their judgements of greyhounds by watching them run. Uller started to make note of the specific running habits of every dog at the track where he was operating. Did a dog instinctively go to the rail? Did he tend to run wide? Did he pop out of the box the instant it opened? Did he hesitate a split-second and then rush into contention?

Once he was operating with the proper tools, learning to anticipate how a race was going to develop, Uller discovered that the greyhound game is surprisingly simple. "There are so many fewer factors here than at the thoroughbred track," he said. "There are really only three that matter: early speed, class and post position." While it may take an aspiring horseplayer a decade to learn the essentials of the game, Uller could master the basics of dog racing in a year or two.

He was intoxicated by his newfound skill. Uller quit his job with the Postal Service and plunged into the game with feverish intensity. He ballooned to 230 pounds, symptomatic of his monomania, because he didn't care about his appearance, about his health, about women. Dogs were his life.

But Uller would realize eventually that playing the dogs professionally requires coolness and maturity. It is a demanding job; conscientious bettors at Hollywood have to study and watch 109 races a week, on six evening cards and three matinees. And they have to stay in action almost continuously, for the nature of playing dogs is much different from that of playing horses.

Horse bettors, whether pros or casual amateurs, wait for the races where they have their strongest opinions and make their largest bets. Most horse players remember with clarity the most important wagers of their lives. But any single dog race is so fraught with risks that few bettors want to stake a substantial part of their bankrolls in a do-or-die fashion.

Uller handicaps a race principally by trying to determine which dog will gain a clear advantage on the first turn; that is the dog sure to avoid all the bumping and jostling in the race. He takes into account only only the inherent quickness of the dogs but also the bias of the race track that day and also any interference that may occur as the field leaves the box. If the public does not share his opinion, and lets his front-runner go off at generous odds, Uller will invest $600 to $1,000 in the race, playing quinelas, perfectas and trifectas.

Although he once won $25,000 on a race, Uller says that he and the 30 or so other professionals who operate at Hollywood don't often make enormous single-race killings. Even a $10,000 hit is something of a rarity. Uller and his brethren don't get to enjoy the occasional spectacular intellectual and financial killings that good horse players do. But they are consoled by the knowledge that they are playing a relatively easy game, with betting pools inflated by a lot of uninformed tourists' money, and that over the long haul they are sure to grind out a profit. It may not be glamorous, but it's a living.