THE PLAYERS.

Erick Lindgren doesn't lock the doors of his home, which is in a gated community in North Las Vegas. This way, his friends, who are mostly professional poker players, like him, can drop in anytime, to swim, shoot hoops, play snooker, or watch sports on a sixty-one-inch projection television--or on any of six smaller plasma screens--in his living room. Lindgren's place is a bachelor pad in the literal sense: it's usually filled with single men. On my first visit, in December, several young Swedes and Danes, in town for the Five Diamond World Poker Classic tournament at the Bellagio casino, sprawled on a vast sectional couch in Lindgren's living room, tracking N.F.L. bets on their laptops and playing online poker. Lindgren, a beefy, blond twenty-eight-year-old from Burney, California, sat at a pedestal desk in the middle of the room. He was wearing flip-flops, a T-shirt, and baby-blue pajama bottoms, and was simultaneously watching the football lineup on the seven TVs and playing online poker.

On a Saturday evening in May, by contrast, the mood in the room was almost ascetic. Lindgren's friend Daniel Negreanu, a thirty-year-old Canadian player who writes frequently about poker and is currently ranked No. 1 in lifetime tournament earnings by the Hendon Mob Poker Database, a Web site that gathers statistics about the game, sat on the couch leafing through a Swedish poker magazine that included a translation of one of his columns: "Den storsta pott jag nagonsin forlorat" ("The Biggest Pot I've Ever Lost"). Negreanu, who is pale and lean, with a scruffy Caesar cut that he colors blond, laughed and read the title aloud in a convincing Swedish singsong; he can imitate anyone he's played with, which, he says, gives him a feel for how an opponent thinks. Soon, Lindgren showed up, to take a shower. He had just lost seventy thousand dollars in a golf game--by playing for ten thousand a hole--against his friend Phil Ivey, another poker pro, but he seemed remarkably cheerful. He said that he had lost fifteen pounds in the past month and was likely to cash in on a twenty-thousand-dollar weight-loss wager that he had made with another friend.

For Lindgren and Negreanu, this was an unusually quiet weekend, the last before the World Series of Poker, an annual event, which runs this year from the beginning of June through the middle of July and culminates in a week-long championship in no-limit Texas hold 'em, currently the most popular version of the game. But the living room seemed different, too. DVDs that had been scattered on the floor in December were now neatly filed in a caddy by the fireplace, and, above the mantelpiece, an oil painting of Kramer, from "Seinfeld," and an oversized presentation check for a million dollars, from PartyPoker.com, were arranged in crisp right angles. Lindgren had hired a housekeeper.

For professional poker players, engaging a housekeeper is not a simple task, largely because of their relationship to cash. They keep a lot of it around, in loose wads; the game both provides and requires it. "It's the silliest thing," Negreanu said, "but I feel naked unless I have some money on me. If I was going to the Rite Aid right here, just to get some shampoo, I would bring six or seven thousand, just in case. Like if, on the way, I had to buy a car." On my first visit, Lindgren's roommate, Ryan Bambrough, had left a tournament buy-in, or entry fee--in this case, three thousand dollars in hundred-dollar bills--on the marble island in the kitchen. The money sat there all afternoon, while Lindgren's guests traipsed in and out, fetching slices of takeout pizza during commercial breaks. To tidy a house that contains so much cash that you have to tidy the cash itself requires a housekeeper who is part saint. Lindgren's friend Jennifer Harman, who may be the best female poker player in the world and lives a few miles away with her husband and four dogs, recommended her housekeeper, Maricarmen Soria. Now Negreanu employs her, too.

Poker is experiencing a cash boom. In the past five years, the first-place prize in the World Series of Poker's championship event has grown from a million dollars, in 2000, to an estimated eight million this year, an increase that can be traced to developments in television and on the Internet that have attracted new players in unprecedented numbers. In 1998, the first online-poker sites made it possible for people to log on from anywhere, at any time. The money flowing into poker sites padded the bankrolls of young players like Lindgren, who won his first online tournament when he was twenty-two and was soon earning seven times what he had been making at his local casino. But the Web sites didn't really take off until professional poker tournaments began appearing regularly on ...