The older, heavyset gentleman -- called "Mr. B" by everyone around him -- was losing big at the casino's blackjack table. The young blond at his side (probably his niece, cracked a bystander) in the tight jeans and sweater tugged at his arm, urging him to stop playing. But Mr. B. wouldn't hear of it. He pushed two black $100 chips into the betting circle and asked the dealer to get him a cigar.

When the first casino opened in Atlantic City four years ago, a young blackjack dealer named Ron DePietro stepped up to deal one of the first legal hands of blackjack in New Jersey.

"Hello, ladies and gentlemen," DePietro said to his table of seven players. "I would like to say that you're my first customers, and I want to welcome you to Atlantic City."

From a man sitting in one of the chairs came an impatient growl: "Just shut up and deal the cards."

For experienced gamblers, the ones like Mr. B who live for ACTION at casino gaming tables, friendly but inexperienced employes like DePietro were part of what was wrong with Atlantic City in the beginning. The tables were too crowded. The newly trained dealers didn't deal cards and calculate pay outs rapidly. High rollers couldn't establish immediate credit, and casinos were slow to extend "comps," complimentary room, food and other perks. To the East Coast player looking for action, Las Vegas was still America's gaming capital.

But the Las Vegas monopoly is over, because DePietro's customers weren't the only ones playing to win in the summer of '78. The State of New Jersey, the City of Atlantic City and, in the beginning, Resorts International, bet a bundle that this country was big enough to hold two states offering casino gambling. And while the merely curious may have brought in enough revenue at first to make the state, city and casino look good, long-term success depended on a steady stream of players.

Last year Atlantic City was America's No. 1 tourist spot, drawing 19 million visitors. And they weren't coming for the salt water taffy.

The floor man standing near Mr. B's table clapped his hands sharply three times. A waitress appeared, and he whispered something in her ear. Within moments, a new box of cigars was opened with some ceremony on the green felt blackjack table. After Mr. B helped himself, the floor man pushed the box in his direction and said quietly, "Compliments of the house, Mr. B."

The most obvious breed of steady players cultivated by the casinos are the so-called bus people: the elderly, the tentative or the limited-income players who arrive by chartered bus at Atlantic City casinos every day, including that very popular day in casino land, Christmas. First-time visitors to Atlantic City can't help but notice the steady stream of buses disgorging players from New York, Philadelphia, Washington and elsewhere; the tour operators advertise regularly in East Coast newspapers, offering travelers a few dollars in casino money and a free lunch.

The casinos calculate that each of the bus people puts into play about $50 or $60 per visit, usually at the slot machines. That is called "the drop," and the drop from bus people is no small change. At Resorts, for example, spokesman Phil Wexler says about 43 percent of the casino's gross win comes from the slots, twice that of the average big hotel on the Strip in Las Vegas.

But in the last couple of years, to the despair of the Nevada gaming industry, Atlantic City casinos have polished their images with the Mr. B's of America. Atlantic City's attraction is its easy accessibility. A big player from New York no longer has to plan a vacation to Nevada to gamble -- not when he can hop a cab to LaGuardia Airport around dinner time, settle into a free flight aboard, say, Resorts' 48-passenger private plane, put in six or seven hours at the gaming tables, and be back home on the other side of midnight.

All nine Atlantic City hotel-casinos compete to capture the affection and loyalty of players who are willing to wager a few thousand dollars a visit. To lure the big player, they offer free suites, gourmet dinners and tickets to shows, and as long as a player is in the chips, he will be accorded the kind of pampering that would make a maharaja envious.

Just ask Ron DePietro, the polite blackjack dealer who greeted his first customers with a flourish four years ago. DePietro has prospered in Atlantic City, and now, as the new vice president of casino marketing for Resorts International, he knows all about high rollers. With his razor-cut hair, beige leather shoes and Rolex watch, DePietro is every inch a professional greeter; his authority to send jets and limousines anywhere to bring in what he calls the "elite player" gives clout to the line he delivers a dozen times a week: "If there is anything you need -- anything at all -- call me."

Working from a list of about 2,000 players, each of whom has at least a $20,000 line of credit at Resorts, DePietro makes sure no one forgets his casino. It's his job to bring in the players who carry in their pockets wads of $100 bills as casually as some people carry chewing gum. If DePietro hasn't seen a high roller in six months or so, he gives them a phone call.

"I should cause, in an average month, about a $1.5 million drop," DePietro says. "I try to do $50,000-a-day in drop."

His players don't have to lose that much, they simply put it into play at whatever game they choose. The odds take care of the casino's profit margin.

"I once brought in a guy who won $500,000," says DePietro, not the least bit upset. "One thing about a player like that, he's not going to go buy a house. He'll go home and say, 'Hey, I killed 'em!' It's like free advertising. Then he'll come back and lose that much and more."

Nothing is too good for DePietro's elite players. When a Philadelphia player called to say he couldn't make it one winter day because his driveway was covered with snow and ice, DePietro promptly dispatched a plow to clear the way. When another player's car broke down 80 miles out of Atlantic City late one night, DePietro sent him a limousine with a bottle of Dom Perignon on ice.

It should go without saying that DePietro's players -- as well as big players who stay at DePietro's competitors' establishments -- are fully "comped," or, as DePietro calls it, "They're RFB," which stands for room, food and beverage. Nearly all hotel charges, from the health club to beach furniture rental, are picked up by the hotel.

As the piles of $100 chips in front of him evaporated, Mr. B impatiently called for another marker, an IOU that he signs in $5,000 amounts up to whatever credit limit the casino has granted him. The markers will be presented to his hometown bank as checks, unless Mr. B gets lucky and can afford to buy them back first.

Newcomers tend to feel sorry for some of the old men and women pulling the handles on the Atlantic City slot machines, waiting for those multicolored symbols to line up, for that light on the top of the machine to begin flashing and the bell that signifies a jackpot winner to begin clanging. Save your sympathy; journalists have interviewed enough of the bus people to know that, for many of them, coming to Atlantic City is a big treat, a break in a monotonous life, a chance to feel that same surge of hope that Mr. B feels when he splits his aces and has $1,000 riding on a bet.

That excitement and tension is what gambling is all about: the jolt of anticipation that accompanies every silver dollar that drops in a slot, every spin of the roulette wheel, throw of the dice or turn of a card. Unlike most gambles in life, the payoff on a casino bet is immediate and crystal clear. For some, that kind of risk-taking (especially because the odds always favor the casino in the long run) is, at least, foolhardy, or, at most, immoral.

But for the beginner curious about whether Atlantic City casino gambling might be interesting, here are some general guidelines:

* The game of blackjack offers the best odds in the casino. If you intend to play it, read a book on the game -- any bookstore stocks general gambling books. Then take a $100 stake and play the $2-minimum-bet tables in Atlantic City. If you can't find a seat at the $2 tables (and the casinos don't make it easy for you), you should have a bankroll of $200 to have a fighting chance at the $5 tables. The Playboy Hotel and Casino is one of the few that offers an oceanside view; Claridge is cozier; Bally's Park Place is flashier; Harrah's offers free parking for three hours (it can be $8 elsewhere); the Golden Nugget is almost pretty; and Resorts and Caesar's Boardwalk Regency are real, all-American casinos as flamboyant as any Hollywood set.

* If you are new in town and win or lose $100 or $200, don't expect any casino to treat you like a big player who deserves free room and board. If you turn your modest stake into, say, $7,000, however, you might find you have some new friends in town. If a casino employee asks your name while you're playing, don't panic; he's not working for the Internal Revenue Service, he's simply "rating" you as a player. Highly rated players are the ones who are extended comps by executives like DePietro.

* Drinks are free at playing tables (unlike, say, London, where the law forbids alcohol to be served in the gaming areas), but try to stick to the soft stuff. And don't play exhausted. Earlier this month, I sat at the $25 tables with a man who said he'd just lost $10,000. His diction was terrible, until he explained to me that the pressure had become so great, he'd gone to his hotel room, removed his false teeth and was back to recoup his losses. It didn't seem as if he was having much fun.

* For your mental health as well as pleasure, try to take advantage of other parts of Atlantic City. If you want good seats for that's night big-name act, find out the name of the maitre d', visit him late in the afternoon when no one is in the theater, give him $20, tell him your name and let him know you have bad eyesight. In the gambling part of Atlantic City, money talks, nobody walks. You pay money, you get respect. And the shows can be first-rate. Frank Sinatra will appear this fall at Resorts and Suzanne Somers, Bill Cosby and Shirley MacLaine have strutted their stuff at the Sands. A generous tip will also get you a table at one of the fancy hotel restaurants, which are frequently booked long before you think of dinner.

If you are an experienced gambler known in the Carribean, Nevada or overseas and want the comp treatment in Atlantic City, call the casino marketing office and explain how much money you will put on deposit in the casino cage. You will probably be received on an "evaluation basis." That means your play will be observed, and if you're a big bettor who plays several hours a day, your room, food and beverage will be on the house.

The sixth time Mr. B demanded a marker, he was quietly, but very firmly, informed that he had reached his credit limit. Mr. B was not happy about that, but his date promised him they could move on down the Boardwalk to another casino where, after some coffee, maybe they would get lucky. Mr. B shrugged. "At least," he slurred as he pushed away from the table, "I got a box of cigars." CAPTION: Picture 1, Atlantic City in its heyday; Picture 2, The Golden Nugget casino, by AP; Picture 3, One of the Steel Pier's diving horses. Copyright (c) Peter L. Gould