Arkady Shevchenko, the highest ranking diplomat ever to defect from the Soviet Union and the author of the bestselling memoir "Breaking With Moscow," fabricated sections of his book with help from the CIA, according to an article in The New Republic that is to appear tomorrow.

Edward Jay Epstein, author of the article, "The Spy Who Came In to Be Sold," said in a telephone interview, "Shevchenko's book is a fraud on the same level as Clifford Irving's fake about Howard Hughes. He creates sources and events that never happened."

The Washington Post reported on June 6 that publishing sources and sources who had helped Shevchenko write the manuscript after his defection in April 1978 said Shevchenko might have "juiced up" certain scenes to make the book more commercial. CIA sources also said that Shevchenko's information both as a "mole" before his defection and after was of limited value.

In his article, Epstein writes, "What is fabricated here are not just car chases, meetings, conversations, reports, dates, motives and espionage activities, but a spy who never was."

He claims that American intelligence created a myth of a "super mole" to make Shevchenko's role seem more important than it actually was.

Shevchenko's saga of working as a CIA mole while serving as an undersecretary general in the United Nations secretariat caused a sensation last February, appearing as a two-part Time cover story, in a "60 Minutes" segment and, finally, as a best seller for Alfred A. Knopf, a subsidiary of Random House. Shevchenko has become something of a media star in the United States, appearing on the lecture circuit for at least $10,000 an appearance. Film rights to his book will reportedly sell for as much as $500,000.

Epstein says Shevchenko made up incidents, details and dialogue throughout the book ranging from a car chase described in the dramatic opening chapter to a scene describing Nikita Khrushchev aboard a boat. Shevchenko tells of spying in 1976 on the New York head of the KGB, Boris Aleksandrovich Solomatin, and provides a verbatim account of a dinner party at Solomatin's apartment. But Epstein says records show that Solomatin was in Moscow at the time.

"The whole thing is a falsification of history," Epstein said.

Time magazine spokesman Mike Luftman, however, said staffers rechecked Shevchenko's story yesterday with new and original sources and found it accurate. He called Epstein's piece "off the mark."

Ashbel Green, the editor at Knopf who was largely responsible for the shape of the final manuscript, reacted strongly to The New Republic piece, saying Epstein had "gone extremely wrong."

"I have to be skeptical right from the beginning because of the person who wrote the article. He's a well-known conspiracy theorist."

Epstein is the author of several books, including "Inquest," a critique of the Warren Commission's report on the assassination of John F. Kennedy, and "Legend: The Secret World of Lee Harvey Oswald," which raised questions about another Soviet defector.

Neither the CIA officials nor Shevchenko were available for comment.

The Post article described how Simon & Schuster had originally paid $600,000 for the Shevchenko manuscript but then rejected it because it was lacking in detail. Simon & Schuster editor Michael Korda said he was "slightly suspicious" when he read the published version issued by Knopf.

"It wasn't just because he never mentioned the CIA [to Simon & Schuster] and the espionage material," Korda told The Post. "The material changed, too . . . That kind of thing makes me believe that Shevchenko's experience with [Simon & Schuster] made him and his people think they'd better juice it up a bit."