East Hampton, N.Y. -- Say it ain't so, Joe.

Surely that was the instinctive reaction of many fans of Joseph Heller's "Catch-22" when it was announced last year that he was writing a sequel to his beloved first novel. With more than 10 million copies in print since it was published in 1961, "Catch-22" for many readers redefined how they viewed war novels. Their feelings about his mordant, wildly satirical novel have always been passionate.

Did Hemingway write "The Sun Also Sets?" Did Melville break down and give us "Free Moby Dick"? They knew enough to leave a classic alone. But now "Catch-22" would be infected with the insidious contemporary virus of serial-itis.Yossarian, Milo and the rest of the deliciously absurd cast of "Catch-22" would be reprised for something called "Closing Time."

"I know how people feel about 'Catch-22,' " Mr. Heller says. Some people may not want to give this new book a chance. But if they do, they'll find it is a very strong and unusual book."

Unquestionably, "Closing Time" is the literary event of 1994. With a considerable first printing of 200,000, the book hit bookstores last week and is bound to be dissected, discussed and, by some, dismissed. Comparisons to "Catch-22" will be easy to make since Simon & Schuster is also releasing a new hardback version of the first book, with an updated introduction written by Mr. Heller. Already, one early reviewer in Publishers Weekly has announced his disappointment with "Closing Time," concluding, "In the end, despite flashes of the old wit and fire, this is a tired, dispirited and dispiriting novel."

But, as Mr. Heller says, he's anticipating a backlash, some second-guessing. He's been holding court with the media for the past month, meeting reporters from around the world at his comfortable home in this extremely high-tone resort in far eastern Long Island. There's a guest house and a heated pool on rolling grounds that are dotted with trees, but, he assures a visitor, "It's a very modest house by East Hampton standards."

He looks good for 71 -- tanned, close to 6 feet tall, robust with

just a hint of a paunch (he swims regularly for exercise). A decade ago, he contracted a neurological disorder called Guillain-Barre Syndrome. It took him years to recover, a painful process described in his only nonfiction book, "No Laughing Matter." He came out of the experience with a renewed appreciation for life, and also a mate: Valerie, his second wife, was the nurse assigned to aid in his rehabilitation.

There's still a lot of his native Brooklyn in his rumpled, informal manner ("Hi, I'm Joe Heller," he announces as he offers a firm handshake) and his earthy, sometimes rambling speech. He may be one of our esteemed novelists, but he retains enough rough edges to seem less a man of letters than a retired union boss.

Rough edges

Even friends say Mr. Heller is moody or sometimes anti-social -- "For 20 years now, I have managed to overlook his frequent sulkiness, his gluttonous table manners and his tendency to growl 'No' before he even knows what the question is," Barbara Gelb wrote recently in the New York Times Book Review. But he usually goes the extra mile for interviewers, and on this day he's candid and often quite funny. (Asked if he had trouble conveying the multiple tones of "Closing Time," he answers quickly, "It wasn't hard because I don't have a consistent personality."

He's obviously proud of "Closing Time," his sixth novel.

"There's always some curiosity, some anxiety inside me when a new book is coming out," Mr. Heller says as he settles into a bench on the front yard. "But this time it's a lot less. I've got a lot of confidence in 'Closing Time,' based on the reaction from my publishers and from other people who have read it.

"It covers a great deal of ground, a large number of subjects, and moves to a conclusion that some people will find incredible, or fearful, but I think, realistically, is inevitable. We're coming to the end of a lifetime."

For more than two decades, Mr. Heller had resisted writing a sequel to "Catch-22," a dark, comic novel about a squadron of reluctant U.S. bombardiers stationed in Italy near the close of World War II. Then, in the mid-'80s, after first deciding against writing one for his then-publisher, Putnam (and returning, he says, an advance of $2.5 million), he reconsidered.

"I began to realize that a sequel to 'Catch-22' could conceivably coincide with my own life since World War II and where I am now," he says. "Then it began to appeal to me."

The tricky part, he soon realized, was deciding how to pick up where "Catch-22" left off, and where he should continue in "Closing Time."

"That was very delicate," Mr. Heller says. "There are two, three, four places where I actually go back to 'Catch-22' in this book. Originally I thought I would use much more of it, and then I realized there wasn't much creative effort in that. Also, I'd be raising the risk of requiring people to have read 'Catch-22' in order to read 'Closing Time.' Just doing a sequel would have been exploitative."

As for the inevitable comparisons between "Closing Time" and you-know-what, Mr. Heller acknowledges, "Some people may say it might not have the energy or the optimism of 'Catch-22' and that would be true -- but that was true of 'Something Happened,' my second novel. Anyway, these are two different books."

Not really a sequel

John W. Aldridge, one of America's leading literary critics, agrees. An early, enthusiastic backer of "Catch-22," he read an advance copy of "Closing Time" and calls it "a kind of connected successor to 'Catch-22,' but not really a sequel."

" 'Catch-22' was an awesome precedent, and it would really be impossible to top a book like that," says Dr. Aldridge, a professor emeritus of English at the University of Michigan. " 'Closing Time' is a strange kind of book. It's beautifully written and an impressive performance. Heller's done the only thing he could

do -- take the main characters of 'Catch-22' and show them in old age."

Of course, Yossarian, the legendarily rebellious bombardier who, the end of "Catch-22" fled Italy for neutral Sweden, is back -- though he does not occupy as prominent a role as he did in the first book (one can hear the howls of protest already). In "Closing Time," Yossarian is 68 and living the comfortable life in New York, which itself is in advanced decay. Yossarian is still paranoid, still both oblivious to the world around him and acutely attuned to it.

As "Closing Time" begins, Yossarian is in the hospital, just as in the opening chapter of "Catch-22." He's sure he is going to die, even though doctors can find nothing wrong with him. Perhaps Yossarian is coming to terms with his mortality, or that of American society: "The cold war was over, and there was still no peace on earth. Nothing made sense and neither did everything else. People did things without knowing why and then tried to find out."

After the war was over, Yossarian ended up working for Milo Minderbinder, who parlayed his entrepreneurial talents of "Catch-22" into becoming head of a multinational corporation. Milo remains a shadowy, elusive figure in "Closing Time," but he does have a couple of great moments in which he persuades the Pentagon to buy his Shhhhh! bomber without having seen the plans (which are nonexistent):

"You can't hear it and you can't see it. It will go faster than sound and slower than sound."

"Is that why you say your plane is sub-supersonic?"

"Yes, Major Bowles."

"When would you want it to go slower than sound?"

"When it is landing, and perhaps when it is taking off."

"Absolutely, Mr. Wintergreen?"

"Positively, Captain Hook."

"Thank you, Mr. Minderbinder."

The congenitally nervous Chaplain Tappman also returns in "Closing Time," and he's got a problem. He urinates tritium, the radioactive substance used in making nuclear devices.

Straightforward approach

Although some of "Closing Time" retains the over-the-top tone of "Catch-22" -- particularly the segments with Yossarian, and in the apocalyptic ending -- much of it is straightforward. Mr. Heller introduces the characters of Sammy Singer and Lew Rabinowitz, Jewish kids who grew up in Brooklyn's Coney Island neighborhood (as did the author). They were among the millions of veterans who came back after the war to become relatively quiet, solid citizens. It is their generation that now faces its own "closing time."

While "Closing Time" often has an elegiac tone, Mr. Heller isn't mourning the end of his generation.

"You know, for the young people, the future isn't as promising," he says. "It's not as good a time for them as it was for me, and I think they realize that. I've seen it happen in New York, certainly, and I would think it has happened in Baltimore as well."

Some of the most haunting passages in "Closing Time" depict a New York overrun with the homeless, the misfits and losers. "I definite- ly wrote the parts about New York with a feeling of regret," Mr. Heller says. "It's a transformation that we can accurately describe as decline. Often when we talk about change, it's meant to be the same as progress, but not in this case. And I believe our government, like all industrial governments, has never found a way to take care of its population."

That's why, he continues dispassionately, "it may be 'closing time' for democracy as we've experienced it. The margins for error are very, very narrow. One of the elements of that is the

inability to control crime.

"Do you know," he says suddenly, "that in the 19 years I lived in Coney Island before going off to war, there was not one serious crime -- not one murder, not one rape? That we cannot stop

crime is one of the manifestations of our country's decline."

'It is gloomy'

"Closing Time" reflects this somberness. Mr. Heller nods when it's suggested some readers may find it a gloomy book.

"It is a gloomy book, with lots of humor and lots of laughs," he says. "That's the same with 'Catch-22.' I'm still surprised when people tell me that 'Catch-22' is the funniest book they've ever read. That may be true -- 'Catch-22' is the funniest book I've ever written."

He says the last slyly, and starts to laugh.

Then, when asked if "Closing Time" deals with concerns about his own mortality, he turns reflective.

"You know, I told an English interviewer for the BBC that this is a good time to be old," he says. "My generation has had a good ride. And I'm not worried about dying any more, not after the illness. I think I can face it OK. No, this is a good time to be old."

FROM "CLOSING TIME"

From the lofty picture windows in his high-rise apartment, Yossarian commanded an unobstructed view of another luxury apartment building with an even higher rise than his own. Between these structures ran the broad thoroughfares below, which teemed more and more monstrously now with growling clans of bellicose and repulsive panhandlers, prostitutes, addicts, dealers, pimps, robbers, pornographers, perverts, and

disoriented psychopaths, all of them plying their criminal specialties outdoors amid multiplying strands of degraded and bedraggled people who now were actually living outdoors. . . . Even in the better neighborhood of Park Avenue, he knew, women could be seen squatting to relieve themselves in the tended flower beds of the traffic islands in the center.

It was hard not to hate them all.

And this was New York, the Big Apple, the Empire City in the Empire State, the financial heart, brains, and sinews of the country, and the city that was greatest, barring London perhaps, in cultural doings in the whole world.

Nowhere in his lifetime, Yossarian was bound often to remember, not in wartime Rome or Pianosa or even in blasted Naples or Sicily, had he been spectator to such atrocious squalor as he saw mounting up all around him now into an eminent domain of decay.