She's propped a snapshot of a cute toddler on her slot machine, and every third or fourth play, Yolanda Allen holds the photo up to the spinning reels, willing them to stop on an auspicious combination of cherries and bars and sevens.

"My grandbaby," she explains. "Love him to death. I put him up there for luck."

It's working, sort of. "I already won $300 off this machine and I started with $20," Allen says, pulling a wad of bills out of her jeans pocket. She's a correctional officer at a county jail about 50 miles inland, celebrating her 37th birthday at Harrah's casino, though she doesn't really need an excuse: She drives down to the Jersey Shore twice a week anyway, just for fun, just because she loves the slots. And she always plays this game, Wheel of Fortune, because she likes the bonus round where the wheel atop the machine spins and adds to her winnings. "Big excitement. Your heart starts to race. You think, whooo. And when it pays you, you're so happy. And then you want to sit here and play all night."

Some people do. The machines take up most of Harrah's almost three-acre casino floor, blazing gaudily in the shadowy lighting, creating a constant electronic din. In the small hours people are still sitting in front of them, hitting the play buttons in a rhythmic trance, smoking, staring, hitting the buttons again, feeding in more bills and coins, winning a little, usually losing a little more, hitting the buttons.

Here's a woman who's playing two Monopoly machines at once while drinking a Coke, an impressive act of dexterity, especially at 2 a.m. Here's a woman who's folded her jacket into a pillow and is napping on a video poker console while at the next machine her friend Mary Eichel, a bus driver from Cherry Hill, N.J., mutters bitterly: "Terrible. They ain't givin' nothin' away. What a racket. Donate, donate, donate." Here's a woman in a black cape -- most slot players are middle-aged and older women -- who arrived at 10 p.m. and is still pumping dollars into a McIlhenny Tabasco Sauce dollar slot at 9:30 the next morning. She paused for dinner but not for bed. "I still lost," she says.

Well, of course; that's the way of slot machines. Players know this, deep down. They understand that despite their sense that a certain routine or machine is lucky, slot-spinning is a random process. They grasp that slot operations rely on the machines' taking in more than what's paid out. So players, even if they pick up a few hundred or a few thousand bucks, will eventually lose if they keep playing -- whichever game they pick, whatever incantations they murmur, whether their grandbaby's photo is tucked behind the coin slot or not.

"Everybody here, we're losers," a genial telephone lineman acknowledges; he's a local who has stopped by for a few rounds of video poker and is down 80 bucks. "You get some enjoyment, but you lose. Unless you win and you leave and you never come back."

But here they all are anyway. Yolanda Allen's Wheel of Fortune is starting to turn on her -- "this machine was so hot. So hot! Then it goes dead like this" -- and she's begun to pull a few bills out of the wad of winnings in her pocket, though she knows this is a sure route to going broke. She decides to head up to her hotel room and rest a bit, then return. "I think you get more hits later in the morning."

This is the sort of illogically lucrative scene that could make a political candidate -- a guy running for governor of Maryland, say -- take notice. Say the candidate, his campaign partly fueled by gaming industry contributions, wins. Say he takes office facing a $1.3 billion budget deficit. Gross revenues from slot machines -- what they took in minus what they paid out -- topped $3.2 billion in Atlantic City last year, recession or no. Harrah's alone, which took in more from slots than any other casino here, made more than $400 million. A governor in a strapped, slotless state might well think: Yeah, we could use a little of that.

Not Your Father's Slot Machines What Maryland Gov. Robert L. Ehrlich Jr. has proposed is known in the industry as "racinos" -- casinos at racetracks. Exactly how many slot machines might be installed at which tracks will be the subject of intense, well, jockeying over the coming weeks. The racing industry initially called for 18,000 machines at five tracks; the governor has spoken of 10,500 at four; slot opponents (including the new speaker of the House, a Democrat) are also weighing in. What licensing fees the state would like to charge, how heavily revenues might be taxed, it's all up for grabs.

As to what kinds of slots might crop up at Laurel or Pimlico by the spring of 2004 if legislators do give the nod, that's where things get interesting. This happens to be a period of revolutionary change in the slot world. Calling them "one-armed bandits," for example, betrays an outmoded concept of design, if not intent. "We'll look back 10 years from now," says Wendy Hamilton, vice president for slot operations at Harrah's Atlantic City, "and say, 'Wow, 1999 to 2003, we went from night to day.' "

A brief retrospective: The first spinning-reel slot machine, invented by a German-born mechanic in 1895 and installed in San Francisco taverns, was called the Liberty Bell. The machines multiplied until, by the 1940s, "you could go to a neighborhood candy store or cigar store or American Legion hall and find slot machines in most big cities, like vending machines today," says Dave Schwartz, coordinator of the Gaming Studies Research Center at the University of Nevada, Las Vegas, which has amassed an unholy amount of information about gambling.

One slot stronghold, as it happens, was Southern Maryland, where a cluster of legal mini-casinos along Route 301 attracted tourists and propped up the economy in four counties.

A backlash in the 1950s -- when congressmen and good-government types denounced gambling for corrupting Americans' morals and feeding organized crime -- rooted out neighborhood machines and largely restricted slots to Nevada. Maryland's strip was shut down in the mid-'60s. By the time the slots started to spread again, picking up momentum a decade ago, the old-style devices were being transformed by two of the more powerful forces of the late 20th century: computers and marketing.

Newfangled slots use video screens rather than mechanical reels, and the potent computer chips behind those screens allow for all kinds of mutations. The symbols that line up (or, maddeningly, don't) can be animated, and appear on nine "paylines" instead of one or three. Windows pop open to offer bonus rounds. "Progressive" machines, linked with other games on the floor or across town, provide mega-winnings; a readout keeps track of the mounting jackpot. The new machines employ a repertoire of digital sounds, too, from applause to sympathetic groans to cheesy game show themes.

"Computers didn't have that kind of firepower before," says Ed Rogich, marketing veep at International Game Technology in Reno, Nev., the nation's largest slotmaker. "You'd get a bell sound when the coins dropped in and maybe a jackpot ring." Now, passing by a bank of "Hollywood Squares" machines, potential gamblers hear Whoopi Goldberg's voice (or Phyllis Diller's) ordering them to "come here, sit down and play."

Slot machines have traditionally been the least intimidating form of gambling -- no rules, no skills, no dealers or opponents, just "something to keep the ladies busy while the men did the serious gambling," Rogich says. Branding them with familiar themes and logos for retro TV shows ("The Honeymooners," "I Love Lucy"), childhood board games, the Miss America pageant (a rhinestone tiara tops the machine), Betty Boop or Spam renders them even less threatening.

The resemblance to other kinds of computerized entertainment -- slots exec Hamilton calls these video games for adults, though most video games actually require far more skill -- is deliberate, and lucrative. In Atlantic City, a slot machine grosses on average $231 a day, every day of the year. Slots bring higher profits than table games like roulette, craps, baccarat or poker, because they don't require dealers and because the casino can set and reset their payouts. (Harrah's says it returns 92 percent and withholds 8 percent of what players spend, which is about average, but in some slot parlors the "hold" can go as high as 20 percent.)

Because consumers are responding to the new bells and whistles -- in the past five years, International Game Technology says, video screen machines have captured 30 percent of the slot market -- and because operators like their bottom line, slots are taking over. They provide the majority of revenues in both Atlantic City and Las Vegas. At Harrah's, the roulette wheels and poker tables are a receding presence, overpowered by 4,233 slot machines in every denomination, row after row after beeping row.

So here's Donna Bentzinger, a psychotherapist from Easton, Pa., approaching what should probably now be called armless bandits. (Slot machine handles, where they still exist, are mostly for decoration.) Tomorrow, Bentzinger will attend a conference on treating sexual abuse victims; tonight she's engrossed in a nickel slot called Double Diamonds.

First she slides in her Total Rewards card -- another marketing ploy -- which prompts an electronic readout to greet her by name. She and her husband, Gregg, a podiatrist, get free meals and hotel rooms for participating in Total Rewards; Harrah's gets an unnervingly detailed profile of which games they play, how much they spend and what their interests are, so it can craft promotional offers to lure them to Atlantic City more often.

Then Bentzinger slides in a five and the video screen fills with diamonds, pearl necklaces and a white-haired jeweler with a loupe. She's playing nine lines, which can create matches in so many directions that hardly anyone can keep track, but it doesn't matter -- "I just let the machine tell me what I've won."

When she hits a winning combination, the guy with the loupe says, "Splendid!" (He has an upper-crust Brit accent.) When she gets a bonus, the screen image changes to a jewelry store, where he invites her to pick five boxes and rack up more points. "Thank you for shopping with us; do return soon," the jeweler says.

Pulse-Pounding Thrills It's a rush, slot players often say. Candy Orzel, celebrating her 33rd anniversary with husband Dave by feeding fives into a machine called Bonus Frenzy, remembers winning $3,700 at Bally's four years back and shrieking. "I'd had triple-bypass surgery the year before -- luckily," she says. "I had to take a nitro pill, I was that excited."

But few of the folks somberly pushing buttons here on a winter weeknight look terribly excited, to tell the truth. If their palms are sweating, they're doing a good job of concealing it; even the winners seem quietly blase.

"It's recreation," a local homemaker named Kim says with a shrug as an attendant counts out the $501.70 she's won after putting 40 bucks into a machine called Enchanted Unicorn. She figures she'll buy her three kids some clothes, take them to Chuck E. Cheese.

So much for what Harrah's calls "pulse-pounding thrills." The dominant behavioral characteristic of slot players here is intent focus on the machine. They tend to play alone, the friends or relatives they came with drifting off a few seats or rows to machines of their own. They don't have to interact with anyone unless they need change. They sometimes talk about losing track of time. Unlike some casinos, Harrah's does have windows, but they're so far away from most players on the vast floor that they provide little in the way of visual cues -- 3 a.m. looks and sounds much like 3 p.m.

Concerned about the tendency of some players to slip into a kind of stupor, the Canadian province of Nova Scotia recently experimented with something called RGF, "responsible gaming features," on video slots. The modified machines incorporated built-in reality checks: they displayed bets in dollars and cents, not credits, which sometimes feel like play money. They had on-screen clocks to let players know how long they'd been at it, and reminders popped up at 60, 90 and 120 minutes to say, "You have been playing for X minutes. Do you wish to continue?" After 2 1/2 hours, no more Mr. Nice Slot; players were required to cash out.

Did it work? Users of RGF machines did significantly reduce the amount of time they played, researchers found -- but they actually spent money faster, the way smokers who switch to low-tar cigarettes light up more of them. Further study, as they say, is clearly required -- and meanwhile, one can imagine the libertarian-tinged fight the U.S. gaming industry would mount against such features. "Ninety-nine percent of our customers are healthy individuals who choose gaming as their form of recreation," says Hamilton, the slots VP at Harrah's. "They don't need that kind of interference. It's like putting a meter on my refrigerator -- 'You're up to this many calories today.' Leave me alone!"

She's right about the numbers -- the prevalence of what public health types call "pathological gambling," a disorder recognized by the American Psychiatric Association, tends to hover around 1 percent of U.S. adults in a given year, numerous studies have shown. (And by the way, if you count lottery ticket buyers, more than 80 percent of adults now qualify as gamblers.) Researchers at Massachusetts General Hospital, studying brain images in real time, report that gambling activates the same neural circuitry as drugs like cocaine. Whatever "causes" problem gambling, "obviously there is a neurobiological connection," says Christine Reilly, director of the Institute for Research on Pathological Gambling at Harvard Medical School. "That's why pharmacological treatments can work."

But most people who play slots don't have a diagnosable disorder. They think slots are fun, in an admittedly mindless sort of way, and instead of spending their recreational dollars golfing or antiquing, they take a few hundred bucks to a casino, which obligingly provides discounted or "comped" room and board. A lot of them are elderly, looking for diversion, finding it here.

Perhaps, suggests the UNLV researcher Schwartz, the slots are also "a way of people coping with diminished expectations" -- not hopeful about achieving the good life through hard work (unreliable) or investing (are you kidding?), they figure they might as well spin the slots. Harrah's takes less of their money, on average, than last year's S&P 500.

They can laugh at themselves, like Barbara Irwin from Wilmington, Del., who's just won $605 in a "Jeopardy"-themed machine and responsibly, prudently set $400 aside for an April vacation -- in Las Vegas. They are often a bit furtive (many people interviewed for this story were reluctant to give their names), not necessarily wanting family and neighbors to know they're hitting the slots twice a month or twice a week, even if they can afford it. They're apt to groan about their losses, but they keep coming back for more.

Yolanda Allen doesn't walk away from her Wheel of Fortune slot with her grandson's photo on it, it turns out. She stays put and feeds the $300 she won right back into the machine, which gobbles it all, and she feels "terrible." But she'll be back in a week or so, she says. Slot players are the ultimate optimists: They can't really affect the game's outcome (the reason that, except for the related video poker, there are no pro slot players), but they still think they can beat the odds.

Which is why a young couple from Mount Pocono, Pa., Paul and Tricia Fratarcangeli, are marking the end of their winter vacation by wandering around the casino floor with a bucket of quarters, about $15 worth. They responsibly decided what they could afford to spend, and this is what remains of it -- when it's gone, they'll head home. So Tricia puts three quarters into a Wild Cherry machine, and then three more, and suddenly they've doubled their money.

And they keep putting in quarters.

"Maybe this last $30 can get us a couple hundred," Paul says. "You never know."

The Wheel of Fortune games at Harrah's in Atlantic City, above, and right, the casino's morning crowd. The windows are so far away from the slots, however, that it's difficult to tell what time of day it is.Scilla Cangro plays video poker at Harrah's, where roulette wheels and poker tables have been pushed aside to make room for endless rows of more profitable slot and video poker machines.All those bells and whistles mean a pretty payoff for Atlantic City casinos. Gross revenues from the city's slot machines topped $3.2 billion last year.Ellen Lariviere tries her luck at a Triple Stars machine. Most of the people who play the slots are middle-aged and elderly women.