"My name is Joe Klein, and I wrote Primary Colors.' "

With that simple statement, the biggest political and publishing mystery of the year was laid to rest yesterday. After The Washington Post discovered Klein's handwriting on a copy of a manuscript of the novel, the Newsweek columnist and CBS commentator was finally forced to come clean.

Klein acknowledged lying to his fellow journalists -- even his colleagues at the magazine and the network -- in denying that he was the anonymous author of the immensely popular satire of the 1992 Clinton campaign. Still, he asserted: "Joe Klein has never lied in a column and will never. My credibility as a journalist has never been questioned." But many members of the political and media worlds expressed dismay over his yearlong deception. Newsweek, whose editor knew about the book, stood by Klein. CBS, which did not know, was taking a wait-and-see approach. The big-budget movie based on the novel appeared on track, as did the paperback. And no matter what happens, he can console himself with his $6 million in royalties.

Klein said at a news conference that conflicts between journalistic honesty and protecting his anonymity were "tough," but he added: "I gotta tell you, none of this has been really terrible."

If Klein was in a forgiving mood toward himself, others were not.

"This was a breathtaking act of mendacity," said 1992 Clinton campaign consultant Paul Begala, who, like many other political figures, has been criticized in Klein's Newsweek columns. "What would Joe Klein be writing about a politician who innocently misstated some detail of his life from 20 years ago? I'll tell you: He'd hammer him. Mr. Klein has clearly failed his character test."

Begala's partner James Carville said, "Am I surprised that Joe Klein lied about writing this book? No, because, in my opinion, reporters lie all the time. This is not a good moment for journalism."

At the contentious news conference, held at Random House's offices in New York, Klein became annoyed as more and more reporters pressed him about his credibility.

"Do I think people should lighten up?" he asked. "Most people are pretty light about this except for the people in this room and a few other people who are . . ."

He appeared on the verge of lashing out when Random House Publisher Harold Evans, who was standing beside him, suggested a tactful way to complete the sentence: ". . . who are doing their jobs."

". . . who are doing their jobs," Klein said, lightening up himself.

Klein's deception has probably also ruptured some personal relationships.

"No one begrudges him the money," said Mark Halperin, a political producer at ABC who covered Clinton's 1992 campaign. "No one begrudges him doing it anonymously in the beginning to protect himself. But on a personal level, many of his friends who asked him directly feel hurt because they're not used to being lied to repeatedly about something they came to care about a great deal."

Said former Clinton press secretary Dee Dee Myers: "He looked his friends in the eye and he lied -- for money."

The attitude at Random House yesterday seemed to be a mixture of hope that this unexpected revelation could be turned to the book's advantage and sadness that the truth had come out.

"He was totally justified in wanting to remain anonymous, and people like you refused to let him," publisher Evans said in an interview after the news conference. "I think you ought to apologize for having routed out the author."

Yet even now, with the secret revealed, Random House will continue to flog the whodunit angle. Evans said the publisher would proceed with its plan to distribute "I Wrote Primary Colors' " buttons at the summer's political conventions "just to add to the confusion."

Klein insisted that his motive in trying to remain anonymous had nothing to do with boosting sales of his book. Rather, he said, he feared reviewers would judge a book by Joe Klein on his reputation as a journalist -- not on its literary merit. Also, he said that as a first-time novelist, he did not want to be embarrassed if he bombed as a fiction writer.

Klein added that he had hoped to keep the secret forever, or at least through many more novels by Anonymous. He noted that Henry Adams published his Washington novel, "Democracy," anonymously in 1880, and that "the author's true identity wasn't revealed until he had been dead for three years. Everyone thought his wife wrote it."

Klein's wife, Victoria, was practically the only person who wasn't mentioned at some point as a suspect. Political consultant Mandy Grunwald, her novelist sister, Lisa Grunwald, cartoonist Garry Trudeau and Newsweek correspondent Mark Miller were all thought to be likely candidates.

So was Christopher Buckley, author of several Washington novels. Said Buckley yesterday: "I think the best line is Sally Quinn's: I was hoping it would turn out to be me.' "

Buckley suggested that Klein use some of the millions "Primary Colors" has earned "to remunerate all of us who did his book tour for him. I don't know how many times I ended up on the radio or TV doing his promo. You can be assured I will be sending him my next book for a blurb. And I don't want it to say Joe Klein.' I want it to say, Best book I ever read -- Anonymous.' "

For a long time, the secret of Klein's authorship was secure. Random House is a notoriously gossipy place, but no one there had a chance to leak the author's identity because no one there ever knew it.

There was only one slip-up. The incomplete manuscript that Klein's agent handed in to Random House in April 1995 had 10 words written on it in the author's hand -- tiny improvements he had made without bothering to print out a fresh copy.

That early production copy was circulated inside the publishing house. Eventually, someone there gave it to someone else, who sold it to a rare-book dealer. The dealer listed it in his catalogue for $200, noting that it was "certainly a most unusual and uncommon early state of the current bestseller."

No one expressed any interest at all until a Washington Post reporter called to ask if, by any chance, this manuscript had any writing in it. Forensics expert Maureen Casey Owens was then hired by The Post to compare the manuscript to a sample of Klein's writing. When they matched, the game was over.

Donald Foster, the Vassar professor who used computer analysis to finger Klein for New York magazine in February, was gracious in victory. "He made some disparaging remarks to me when he was denying authorship, but one has to let that roll off one's back," he said.

Foster, one of the first to make the case for Klein, seemed to be one of the last to accept it. "I still think it's possible that Mandy Grunwald may have done some tinkering," he said.

Former New York governor Mario Cuomo, who shows up in the book as "Orlando Ozio" -- the governor whose fantasy is a presidential race where "where he doesn't run and nobody else wins" -- commented that "Joe Klein said that he would stake his journalistic credibility on the truth of his statement that he did not do it.

"I said at the time, I know Joe, and he would not do this. He would have thought of a clever response. He would have evaded and avoided but would not flatly contradict himself.' I can't accept it. It doesn't make any sense to me."

Dee Dee Myers was incredulous: "He said this would have no effect on his credibility? What planet are you broadcasting from, Joe? He's going to have a long, hard climb back to where people will trust him."

At the White House, spokesman Michael McCurry said, "The president did not seem particularly surprised by the disclosure."

"Primary Colors" has 1.17 million copies in print, making it one of the most successful first novels in recent publishing history. In two months, Warner Books will print 1.5 million paperback copies -- a number that went neither up nor down yesterday. Warner executive Larry Kirshbaum said the book will still be credited to Anonymous, not Joe Klein.

Producer-director Mike Nichols, who paid in excess of $1.5 million for the film rights to "Primary Colors," said that he did not think the announcement would affect the upcoming movie. "My problem is the same as it was before -- turning a first-rate book into a good movie."

He said he learned of Klein's identity at yesterday's news conference.

"I disbelieved it when I read it in New York magazine," said Nichols, reached at his home on Martha's Vineyard, "because it was New York magazine."

The film, estimated to have a $65 million budget, is scheduled to begin shooting in January. Tom Hanks and Emma Thompson have been cast to play presidential candidate Jack Stanton and his wife, Susan, while Jack Nicholson will play the role of the president's electoral rival, and John Malkovich will play the president's campaign manager. Elaine May, Nichols's long-standing working partner, is about halfway through the screenplay.

Esquire columnist Jeannette Walls, who worked closely with Klein when they were both at New York magazine, is convinced that Klein secretly wanted to be found out.

For instance, in the first paragraph of the novel, the black narrator confesses, "I am small and not so dark." As Prof. Foster noted, "klein" means "small" in German, so the sentence really meant "I am klein -- and I'm not really black."

Then there was the May 19 article in the New York Times Book Review, in which Anonymous rambled about suffering from "post-traumatic success disorder," said the frenzy over the authorship was "pretty perverse and occasionally nauseating" and said he would never confess his identity because it would be "a moral breach of some sort."

"The attention was dying down, so he was trying to stir things up again," said Walls. "It was like the Unabomber sending out letters -- he was mad he wasn't getting attention."

Klein denied having any such motives, even subconsciously. "Why would I want to be caught?" he asked with visible weariness. "Why would I want to go through this crap?" Washington Post staff writers Dale Russakoff in New York, Sharon Waxman in Los Angeles, Joel Garreau, Roxanne Roberts and researcher Bobbye Pratt contributed to this report. CAPTION: Newsweek columinst Joe Klein, center, and Random House Publisher Harold Evans meet the press in New York yesterday. (Photo ran in an earlier edition) CAPTION: JOE KLEIN