LAS VEGAS, JUNE 3 -- Selling books, unlike selling shoes or breakfast cereal, is still a primitive, mystical affair: one bookseller, one reader, one book at a time, and no two transactions quite alike. Booksellers have to have a plausible answer when the customer comes through the door and asks: What do you recommend today?

John Updike, appearing here at the annual American Booksellers Association convention, applauded "the heroism of trying to sell books in a post-print era." Heroic it may be, but it is also becoming a profitable labor of love.

There is a wintry gloom at one end of the literary food chain, as the big publishers reckon with the squandered advances and boneheaded book ideas of past seasons. But at the other end, where the books are entrusted to the customers, there's still a ravenous appetite.

So it is that publishers flock to this booksellers' bazaar, bearing news of their fall books and sometimes proffering the authors themselves, and laboring mightily -- with everything from good eye contact to $50,000 theme parties -- to make an impression on the bookselling troops.

Updike used the occasion (2,000 booksellers eating cold scrambled eggs this morning) to talk about his fourth and last novel about Harry "Rabbit" Angstrom, "Rabbit at Rest," by telling how he came to write each of the books in the ninth year of a decade, a reflection of the times and of himself.

The "dodgy" Rabbit, his maker said yesterday, was ambitious at the end of the 1950s ("Rabbit, Run"), distressed at the end of the 1960s ("Rabbit Redux") and "full of beans" at the end of the 1970s ("Rabbit Is Rich"). At the close of the 1980s, Updike said with an effort at a twinkle, comes "sort of a depressed book about a depressed person written by a depressed man."

No doubt the booksellers will think of some other way to describe "Rabbit at Rest" to their customers.

Sharing the platform with Updike was the deservedly cheerful Amy Tan, whose first novel, "The Joy Luck Club," had an amazing run on the bestseller lists last year -- testimony to the power of word of mouth and bookseller belief.

Tan, appearing to promote the newly released paperback edition, revealed to booksellers the real reason her novel sold so well: "the cover." For the jacket art, she said, she chose a powerful subliminal symbol drawn from Chinese myth. Its meaning is: "Buy this book and your children will get into the top three universities of their choice."

Such Cinderella stories as Tan's energize small and large publishers to believe in breakthroughs and surprises -- not a hard sentiment to instill in such romantics as booksellers must be. But the money and the talk in Las Vegas, as every year wherever the ABA meets, are on the sure thing, the can't-miss book -- terms deployed with nervously crossed fingers -- like the latest from Colleen McCullough, Stephen King, Jean M. Auel and Jackie Collins.

Crown, Auel's publisher, hoping for best-selling inevitability, threw a huge cocktail party for her new novel-of- prehistory, "The Plains of Passage." The setting was a cavernous hotel ballroom decorated with extinct life forms and plunged into authentic period darkness, echoing with the nightmarish screeching of wild animals trapped in rock-concert speakers around the room.

Such hype surrounding authors with marquee value may have little carryover to the rest of the book business, observed the ABA's energetic executive director, Bernard Rath, today, but he conceded that it "boosts the industry's confidence" by feeding "the star syndrome that Hollywood has so successfully exploited to keep an industry that is even smaller than the book business in the limelight for lo these many years."

Such big-bucks phenomena also pay the bills for what's known as "literary fiction," the eternally mixed blessing of the "good" book. This fall and beyond it will be honorably represented in the bookstores by new work from Gabriel Garcia Marquez, Norman Mailer, Nadine Gordimer, Larry McMurtry, Tony Hillerman, Ian McEwan, Richard Ford, Jill McCorkle, Mario Vargas Llosa, Clyde Edgerton, Charles Palliser, Jamaica Kincaid, Sue Miller, Geoffrey Wolff, Brian Moore, Diane Johnson, Paul Auster and T. Coraghessan Boyle.

Other authors on whom varying degrees of hope and advance money are pinned include Donald Trump once again, Angela Lansbury, Kirk Douglas, Carrie Fisher, Russell Baker, Larry King, Danny Thomas, Ken Kesey, Isabel Allende, Elmore Leonard, Cleveland Amory, Jane Goodall, Charlton Heston and Malcolm Forbes ("Women Who Made a Difference").

The Washington book, so much in evidence in recent seasons, seems to be under a restraining order -- apparently waived in the case of Ronald Reagan, whose memoir is "the publishing event of the year," predicts Simon and Schuster. Reagan's protocol chief, Selwa "Lucky" Roosevelt, will publish her memoir too, and his CIA director, William Casey, gets a full-length biography from Joseph Persico. Look for new books on Richard Nixon and Dwight D. Eisenhower, and one by Mildred Kerr Bush, who is her ghostwriter Barbara Bush's irrepressible dog.

Major trade books get a disproportionate amount of attention. What keeps booksellers in business -- which is to say, what their customers buy -- is all over the map.

The 1980s saw a flowering of specialty bookstores, for children's books especially as baby boomers began to turn their children on to books, but also for travel books, mystery books, computer books (and software), gay and lesbian books, feminist and ethnic books, New Age books. The booksellers' association estimated that a quarter of the booksellers on hand in Las Vegas represent such specialty stores.

The general independent bookseller today is thriving for a lot of reasons. Just as the chains (Waldenbooks, B. Dalton, Crown) have lately come to learn something from the expertise and service of traditional bookstores, so too, because of competition from the chains, the smaller independent operations have had their minds powerfully concentrated on becoming well-run businesses. Computerization and improved mechanisms for special orders from publishers and wholesalers are two technical explanations for a thriving trade.

Bookselling is a $7 billion business, and despite Updike's observation about the "post-print era," it doesn't look to stop growing. Rath credits the information explosion itself, so closely tied in the public mind to microprocessing technology, for the health of the bookselling business.

"The public is continuing to search to have specific needs addressed and {readers} consistently find books reliable because, by their very nature, books allow an argument to be made to its fullest, an idea to be explored, a skill to be taught," Rath said.

But even as the bookselling trade grows (4,000 people in the last two years have made inquiries to the association about opening bookstores, and 500 of them already have), Rath pointed out the modest reality of the numbers.

"For an industry to convulse in paroxysms of joy when it sells 2 million copies of a hardcover in a land of 200 million adults is, to say the least, odd," Rath said. "Our industry is a notorious underachiever; we should be selling tens of millions if not hundreds of millions of copies of books."

Selling millions of copies of books is a relatively rare achievement in any case. This is a many-cottaged industry, each cottage happy in most cases to count books sold and dollars earned in the mere thousands. They represent a democratically inspiring (and occasionally profitable) variety of passions, hobbies, theologies, aesthetics and gimmickries.

"Sin Boldly -- But Trust God More Boldly Still" is the title of William Boggs's new book, and he had the booksellers stacked up a score or more deep to get free copies, autographed. Spider-Man and Garfield were here again, wandering around malevolently. An inspirational illustrator from Adelaide (Andrew Matthews, author of "Being Happy!") was doing lightning caricatures at his aisle-side stand. A publisher made his straight-faced pitch wearing foam rubber antlers and a red nose. There were many, many earnest little presses, named for animals or shrubs, where the type is hand-set and the binding hand-sewn. And rows of booths offering booksellers the promise of "traffic-building" sidelines -- magazines, tapes, calendars, espresso-makers, greeting cards, rubber stamps, sundials, shoelaces, shelving, video games, humorabilia, software and lots of pink and blue and red and green furry things that bounce up and down.

Sometimes the "real" publishers are perturbed. "The ABA is becoming very expensive, and having been a supporter of the convention for many years, we object to being treated the same way as the fortune cookie and sunglass salespeople," Putnam-Berkley's David Shanks told the daily convention newspaper issued by Publishers Weekly.

The alien surround of this year's convention location proved remarkably benign.

Most of the nearly 25,000 conventioneers were here for the first time, eyeing the acres of slot machines with condescension, wariness and ill-disguised curiosity. After long, ache-footed days in the white static we-could-be-anywhere atmosphere of the convention hall, even a Tom Jones concert after hours could take on a naughty allure.

While some publishers sought in vain for book-party settings that might seem literary or genteel, they ended up usually with acres-large "mansions" upon which decorators had preyed.

More sensible others went with the Las Vegas flow. Crown, to honor Mark Childress's novel "Tender," offered dinner followed by "nudes on ice" -- a much-sought-after invitation for a reportedly disappointing display. Avon celebrated its best-selling author Johanna Lindsey with a dinner at Chapelle L'Amour Wedding Chapel, where nuptials were spoken all about as the booksellers dined.

Harpercollins (the new name for Harper & Row) seemed on to a very good thing, Las Vegaswise, with its fall offering "The Encyclopedia of Bad Taste," by Jane and Michael Stern. Poolside at Caesars Palace, herds of conventioneers were confronted with an almost unimaginable display of kitsch -- tables groaning with junk food, hideous cakes, ice sculptures, candy and cans of Spam; execrable impersonators of Liza Minnelli, Lesley Gore, Pee-wee Herman, Dolly Parton and Elvis Presley; a mime, a bodybuilder, a Roman soldier in armor, and the uproarious chance to have your picture taken with your arm around a nearly naked girl.

And yet this artful cacophony of bad taste really couldn't hold a candle to the culture just a few paces away.