Stephen King and Peter Straub are laughing because someone has just called their best seller "The Talisman" seamless.

Even before they started, their publisher was in a panic over what he insisted on calling the seamlessness factor. He needn't have worried. All he had to do was listen to them talk.

Straub: They wanted us sitting on coffins.

King: The woman came to my house and she had this suitcase and there were two hangman's nooses in it. Nooses! Yeah, and she wanted my wife and me to pose in them . . .

They have just spent the morning doing photos for a magazine. People always want to pose them with some ghoulish hokum.

Straub: You believe this? Imagine someone coming to your house . . .

King: I stopped and thought about it. Do I need this? And my wife, she's looking at me -- I said no.

Straub (through the general laughter): You did put the skull on your head.

King: Yeah. Another reason for not doing this kind of thing is because I am my own worst enemy. Total ludicrousness sets in . . .

The entire exchange takes about 20 seconds. Electricity crackles between them. The remarkable thing about the Straub-King collaboration is not that it happened but that it took them so long to think of it. Even though, as they are the first to say, their writing styles are quite different.

Surely you know that Peter Straub is the author of the spooky smash "Ghost Story," as well as "Shadowland," "Floating Dragon" and several earlier novels, such as "Julia," which have just been reissued. And King has been papering the landscape for years with the likes of "Carrie," "The Shining," "Christine," "Pet Sematary" and other immensely popular books, most of which have been translated onto film.

Today they are having lunch in King's suite at the United Nations Plaza Hotel, with a curious bubble window overlooking half the East Side. Straub wears a tie, drinks chilled white wine, munches on a sliced turkey sandwich. For King it's an open shirt, beer, hamburgers.

It all started with a Thanksgiving dinner.

"When my first horror novel was published," Straub says, "it was sent out for people to do blurbs, and this one guy wrote about it so well, I saw he was on my wavelength, and I read his book 'Salem's Lot' and was bowled over. So I wrote to Steve and said, 'You write wonderful books . . .' "

At the time, Straub was a relatively obscure writer scraping along in London. When King moved his family there briefly, the two met for a drink.

"I was living in a place called Fleet," King says. "It sounds like an enema, which is kind of appropriate. I was trying to get a novel off, but not too much was coming. I mentioned we liked doing the same thing and it would be fun to collaborate, but Peter was under contract for two books and I had various commitments, so we put it off for three years."

Then came the famous dinner at King's place in Maine.

King: Peter's agent was there, too.

Straub: Oh, it was cold. I remember the cold, waxen walls, and the turkey wouldn't defrost so we had roast beef instead. We pretended to be spacemen with the children, making up stuff. My agent was aghast.

King: We were out in the front yard, drunk out of our minds, trying to chop wood. We talked a lot . . .

Gradually the ectoplasmic idea turned into firm reality. By this time Straub had moved to Westport, Conn., because his hit with "Ghost Story" had made it too expensive taxwise for him to live in England. The two men realized that a joint book could be published without too much strain on existing royalties. And they discovered they had a publisher in common.

Straub: He believed in us. He stepped forward with his hand over his heart -- "Talk to me, my boys . . ."

King: We didn't have the outline yet. We made the deal and then thought up the story.

Straub: Well, we knew what we wanted to do, what kind of story. We had a one-page description.

King: They asked us for an outline, and we had one, but we never let 'em see it.

Straub: Good thing, too. It was all changed. It was much too ambitious, like eight novels.

They started to write. For four days they worked together at Straub's house. They plotted on yellow pads ("you could have this happen because you had that happen previously"), and finally King typed it all out in a coherent, logical form.

A lot of people had been waiting for this moment. The money men wanted to see if it would fly, if the styles would fit together. The seamlessness factor. But the writers weren't worried about that.

"I don't plot," King remarks casually. "I usually know where I'm going, and I think I know how I'm going to get there. Things fall into the chain. But it rarely turns out exactly. In 'The Shining,' originally, they all died and went into the spirit of the hotel. There was no black man in it."

The character he is talking about was a catalyst to the plot. The addition must have cost untold hours of tinkering.

"The fact is, we're professionals. We do this for a living. We do a lot of work. Had to cut a lot, which is not my favorite thing. I become churlish and want to save everything. But we knew what we were up against. I can say that," King deadpans, "because I've been to Famous Writers School."

They bought word processors and hooked them up to each other.

King: It was Peter's idea. We could write them off. I've got $15,000 worth of Wang equipment that is now worth $3,000. But the major idea was instantaneous communication.

Straub: The underlining was the only problem. And figuring out "global search."

King: Peter wrote the first longish chunk of the book where I'd left off, and he sent it to me. In three minutes I got 35,000 words of copy.

That's half a novel right there. This could be what King means about being professionals.

Offhandedly he tells of characters, events and whole subplots that were jettisoned, not to mention incidental narrative ("there was more about everything"). At the end, the writers huddled for a marathon editing session. Each one made the cuts he wanted, in both his own and the other's material, with the unspoken understanding that the cuts were final.

They had no fights. None at all.

"I can't remember even bitching privately to my wife," King says.

A liberal intensely concerned with nuclear holocaust, King may be somewhat more political than Straub, but they don't get into politics much. Straub recalls one time when he sounded off about peace marches, but it doesn't seem to have made a dent in their friendship.

Now and then one of them would feel dubious about his ability to write a particular scene or character and would hand it off to the other. They didn't divide chapters, had no regular tradeoff, no rhythmic alternation. One would run for 100 pages, the other taking the next 50, then switch for the next 100, back for the next 200 and so on.

One character gave King so much trouble he asked Straub to handle that part. But now Straub reveals that he thought King caught the character's raucous voice far better than he did.

Fans can spot typical Stephen King devices, like breaking off in midsentence to echo some key phrase. And Straub likes to slip in the names of jazz musicians when he can. But even these clues are unreliable. For a gag, the writers parodied each other's tics.

"It's a little way of saying hi when he's in Maine and I'm in Westport," says Straub.

Half the time they can't tell who wrote what. "It's like trying to think what you had for lunch on Monday," says King. Chapter 2

All right, how do you go about writing a bestseller?

Not just any old bestseller, but a book that in its first week sold faster than any other in history, at $18.95 yet, a book that started off with a world record first edition of 630,000 and already has had two more printings of 75,000 each?

The first thing you do is think a lot. And read.

"We were both interested in 'Huckleberry Finn.' A picaresque tale like that," King says. "Maybe a quest. In 'Finn,' the symbol of movement is the Mississippi River. We had the interstate highway system. The rides Jack got were his raft."

In "The Talisman," Jack Sawyer is a 12-year-old boy who voyages into a strange world, parallel to ours and peopled by doppelgangers of his real-life friends and enemies, in a cross-country search for the magic crystal ball that will cure his dying mother.

The authors wanted an epic quality, so they started reading books about the hero as a concept. Joseph Campbell. Lord Raglan. Searching for ways to create resonances, they took another look at J.R.R. Tolkien's "Lord of the Rings," which they both admire. But they wanted to keep the references contemporary, generally avoiding the Arthurian and Homeric. And they were especially wary of the so-called fantasy genre that has metastasized since Tolkien.

"Neither of us reads much fantasy stuff," King adds. "I find the post-Tolkien people unreadable. We know who they are, we go to the fantasy conventions sometimes, but I don't believe this book will be very well received by them because it's not exclusionary. The thing with this book is you don't have to learn an entire other language. That's a technique of immature writers and readers. They put in all these made-up things, a wingwah or a hoodybody, and you don't know what they are unless you've read the last three books in the series. The only invented word we used was Twinner, and it was carefully capitalized and set off."

Both men read constantly. Modern fiction, biography. Straub is reading Susan Cheever's book about her father. King is deep into "Books of Blood" by Clive Barker. "Reading in the field," he mutters.

"Some kinds of fiction I don't like," says Straub. "The ones with that detached voice, ironic right down to the bone. You can't tell if it's serious. There's this assumption that fiction is an outmoded enterprise and can always be approached in this jokey way." He likes Ross MacDonald, John D. MacDonald, Jack Finney and other craftsmen but at the moment is concentrating on Vietnam books, for his next novel.

They talk about the difference between fiction and literature. "Literature is always aware of itself," Straub decides, "watching itself, narcissistic. All fiction is supposed to do is make the world go away."

"Popular fiction is a good bowel movement," King notes gravely. "Literature is taking stool samples."

Reading evidently stimulates their imagination. Anyway something stimulates it, because both of them are tremendously, unendingly inventive. Anything can set them off. They set each other off.

Somebody comments about the knee-jerk reactions of photo editors, the cliche' pictures they suggest, in graveyards and so forth. (One editor wanted to have King giving Straub a piggyback ride. "How's that for a metaphor?" Straub murmurs.) "It's like every time you take a picture of a black writer, he's got to be picking his teeth with a wooden match down by the swee'pea patch," says Straub -- and instantly the two of them go into a riff about good ol' country boys named Hoss and someone called Miss Polly, and before you know it they have outlined a whole little scene. Without even trying.

From a few offhand remarks about what was left out of "The Talisman," you realize that they must have written thousands of pages of perfectly usable material to produce the 645-page novel. It is work.

"It's a long, hard slog," Straub says. "We've both got elements of burnout."

"We're tired," King agrees. "Two years of solid writing, then five months of extremely bitter, protracted film negotiations. That was the worst part, the strain on us. A lot of people in the business said if you value your friendship, don't do this."

Will there be another joint book? They don't know. They always give different answers to that one, they say. "We think kind of a maybe." Meanwhile, Straub has his Vietnam novel and King is writing a screenplay and polishing a book of stories. He has six other novels in the drawer, he says. When he's not on promotion trips he works more or less constantly at his two places in Maine. Straub has a New York apartment along with his Westport house. Both writers have families: King three children, Straub two.

"One thing people are always asking, even on a TV interview," King laughs. "They want me to tell 'em a ghost story. That's one thing I can't do -- I can't tell stories."

"Yeah," says Straub. "one time my friends gathered the kids around and said come on, tell us a story, Peter's gonna tell us a story now. I finally came up with an old invention, but I'm no good at it."

They nod at each other. Yeah, they can agree on that. They can't tell stories for beans.