So what if Bill Novak wrote every last word of "Iacocca" -- the fastest selling hardback book in the history of publishing -- for a flat fee of $45,000 for two years' work.

And so what if six months ago, when the book was in the process of earning an estimated $5 million for Lee Iacocca's philanthropic foundation, Novak was, as he likes to say, "looking for work."

These days William Novak, 37, author, collaborator and aficionado of Jewish history and culture, is busy rocketing his way up the ladder of publishing prosperity.

Tomorrow just might be Novak's real payoff from "Iacocca." By the close of business -- the deadline of a week-long auction for the rights to House Speaker Tip O'Neill's autobiography -- Novak and the speaker of the House just might have a million-dollar deal.

No flat fee this time.

We're talking percentages.

We're talking a piece of the action. We're talking August on Cape Cod with O'Neill.

We're talking a minimum fee.

"No comment," says Bill Novak crisply.

The success of "Iacocca" has been something of an enigma to the publishing industry. Published by Bantam Books last October, it is in its 33rd printing, with 1.85 million copies in print. (The Chrysler Corp. chairman has donated all his earnings from the book to the Mary Iacocca Foundation, an organization he created in memory of his late wife.)

As of Sunday, it will have been on The New York Times best-seller list for 33 weeks (32 of them at No. 1), and The Washington Post list for 32 weeks. With the exception of the Bible, and perhaps some reference books and cookbooks, "Iacocca" is the biggest selling nonfiction hardback ever. "That's what we have been saying, and no one has rushed forward to argue with us," says Stuart Applebaum, spokesman for Bantam.

"No comment," Novak says crisply, when asked what goes through his mind as "Iacocca" tops the charts.

"Without Iacocca there would be no book," says Novak. "He is the author. [The cover of the book lists Iacocca as the author "with" Novak.]

"Let's be clear," he says, when the sticky question of finances arises, "the deal was never with Iacocca. I doubt he even knows what the terms were. Bantam made me an offer and said take it or leave it. I took it knowing that it might cause some pain but that it was a good career move."

He has just finished a book with Herb Schmertz, Mobil Oil's high-profile Washington lobbyist, and he is currently busy listening to Sydney Biddle Barrows, the "Mayflower Madam," tell her tale of money, prestige and women-for-hire.

"This guy is tremendously hot," says Novak's agent, Steven Axelrod. "I have received about 100 calls from people all over the country asking for him to write their books. He is the collaborator of choice."

Novak can only hope for a similiar boost from O'Neill's book. With Tip O'Neill as the "author" and Novak as the actual writer, industry sources do suggest that the memoirs could generate upward of $1 million. (Sources close to O'Neill and Novak say they are looking for a threshold offer, without which they will walk away.)

Of particular interest to publishers is whether O'Neill, from the old school of zip-lipped pols, is ready to tell the real story of his 50 years in politics -- warts, vendettas and all.

"Unlike Iacocca," Novak's proposal to the potential publishers says, "O'Neill is willing to talk about his mistakes as well as his accomplishments."

But will he tell all?

"How open is he going to be?" says Novak, a soft-spoken intense sort who at once exudes baby-faced vulnerability and the instincts of an operator. ("A hustler," explains his wife, Linda Novak. "Billy is always working his connections.")

"Several publishers have called me to ask how open he's going to be," he says. "I say you have to ask Mr. O'Neill. I don't speak for him. I know that he is more candid than most public figures. I also know that he is not out to get people. He's not vindictive. He doesn't have a revenge motive. I'm careful not to make promises."

Smart guy, Bill Novak.

Novak says he decided to write the book for Barrows -- recently indicted in New York for running a sophisticated call-girl operation, and nicknamed the "Mayflower Madam" because of her lineage -- because it seemed out of character for him. Eleven filmmakers are currently bidding on the movie rights.

"I think I decided to do it because it was a little naughty," he says, "and it was not the type of book people would expect from me . . . She has a great story to tell and she has huge legal bills."

But it is O'Neill who has long been one of Novak's most hoped-for subjects and, in fact, he approached the Speaker first. In the end, O'Neill settled on Novak from a field of 10 writers, based in part on Novak's success in capturing Iacocca's voice on paper.

"I wanted to do Tip's book because I admire his values and because some of those values are out of favor today," he says. "Well, I believe there will be a time when his approach will come back. I think it is important to articulate those things and keep them alive.

"I went after Paul McCartney, too," he says, "but he wasn't interested right now. That is my dream book."

Novak's daily schedule:

8:30 to 11:30 a.m.: Transcribe tapes from his subjects and ogle his IBM word processor. "Very intense work. Sometimes I only really work two of those hours," he explains.

Noon to 1:00 p.m.: Lunch. "I like lunch breaks," he says.

Afternoon: Pick up his two sons, Ben, 6, and Jesse, 3, at school. Phone calls.

This morning he has already been called by "Iacocca" publisher Bantam, informing him that "Good Morning America" wants to interview him this week; by Sydney Biddle Barrows, to let him know her defense is going well; and by his wife. Someone wants to do a story on her Jewish dating service, "New Possibilities."

Things are hopping.

"You have to understand this is all very new to me," Novak says. "I don't feel famous. And I'm not rich. Now I can afford to live here."

Novak's huge house in this affluent Boston suburb has the lived-in feel of the home of a young family. The furniture is basic and modern: off-white couches, leather chairs and a smoked-glass coffee table.

From a stuffy office about as big as a bathroom, Novak structures his day. His thoughts are organized. His office is a war zone. His files are on the floor. "All I need is to be able to concentrate on the word-processing screen," he says. "I could work through a hurricane."

From this cubicle he has crafted three of his own books: "The Big Book of Jewish Humor"; "High Culture," about people's personal experiences with marijuana; and "The Great American Man Shortage," which inspired his wife to start her dating service.

Having edited what he describes as two "Jewish intellectual magazines," "Response" and "Moment," he and his wife like to joke that he quit his only salaried job in 10 years the day after they were married.

Born and raised in Toronto, Novak graduated from York University there and then spent some time writing in New York before settling in Massachusetts about 15 years ago. He says he is from a traditional Jewish family and spends most of his free time on his labors of love, as he calls them. He is involved in Jewish community projects, speaks often before Jewish groups, and edits "New Traditions," a new eclectic magazine about contemporary Judaism.

"When we got married he told me he wanted to keep a kosher house and I thought, 'What is this?' " says Linda Novak, a fast-talking pixie with a fondness for quipping, "Let's be real!"

"Growing up Jewish in Connecticut, I only knew one family who kept a kosher house, so at least I knew what it was," she says, going into a Joan Rivers-type monologue. "And for a while there, I mean, I was hostile about it. When he went out of town I would relish mixing all the foods together and eating them -- on paper plates, of course. I mean, I wouldn't want to spoil the dishes.

"When we got married we were like night and day," she says. "He said, 'I'm a writer,' and I said, 'That's terrific, I don't read.' He was into poetry and I was into loudness. But as you can see, it's all worked out."

Novak says the success of "Iacocca," has baffled even him. "I can account for 2- or 300,000 copies, but I can't account for 1.8 million copies," says Novak. "I don't think anyone can. The man is immensely popular. He's a hero."

Are Novak and Iacocca now friends?

"I got this autographed copy of the book in the mail," he says, showing the inscription: "Dear Bill, Many thanks for putting up with me for two years. Without you it wouldn't have been much of a book."

"It was never a social relationship," he says. "Iacocca makes a strong distinction between work and family, and this was work. That's why I never interviewed him in his home."

He protests politely when asked to pose for photos with the book. "I'm not wild about this," he says, fetching his autographed copy. "I mean, it's less my book than anything else."

"Sometimes we would joke that maybe Iacocca would come by the house and drop off a car to thank us for the book," says Linda Novak. "Yesterday, I was outside and a huge limo started to come up the street, and I thought, 'My God, he's coming.' But then I saw it was a Cadillac."

The book is essentially a classic success tale of how an immigrant's son made it to the presidency of Ford Motor Co., got fired, and then rebounded at Chrysler, guiding the plummeting company through the government bailout. There are good guys and bad guys, and a detailed look at corporate politics.

Novak estimated he spent a total of 48 hours taping Iacocca over a period of 20 months, which is an unusually small amount of time for a project of this magnitude. He also immersed himself in Iacocca's meticulously kept files, read yellowed newspaper clippings and even purchased two Chrysler cars.

"When you're doing a collaboration, you're buying into that person's self-perception," he says. "I wanted to be convinced."

Novak says that Iacocca's colorful way of speaking facilitated his work. "He has a style, a very distinct and animated way of expressing himself," he says. But there were a few problems.

Novak's first draft of the book was rejected by the publishers because, he says, the publisher told him "it was too well written."

"What they meant was that it was my writing style," he says, "and it didn't sound like Lee talking, so I had to go back and rewrite."

The challenge also came when some of Iacocca's words were a little too colorful.

"It's true," says Novak. "The man speaks bluntly, but he's not the most profane person I ever met by a long shot. I decided to save one obscenity for the climax of the book . . . They wanted to take them all out but I fought for that one."

All things said, Novak concedes that he does not intend to be a professional alter ego for the rest of his days. In fact, he sort of looks at it like a neighborhood developer before he has enough money to build his skyscraper.

"Look, there are a lot of books that I'd like to write that I can't get the money for right now," Novak says. "There are several books about the Jewish community I'd like to write. I'm very interested in people's religious practices. I would also like to write a book on the tofu industry, and perhaps another book on marijuana.

"I am not going to spend the rest of my life doing collaborations. Let's just say these collaborative projects help me support my dreams."