NEW YORK — Philip Roth says he's done with Nathan Zuckerman. But is Nathan done with Philip Roth?

"Goodbye, Nathan Zuckerman," the headline from Time magazine reads. Roth, the story declares, "has exhausted the possibilities of his character," the fictional adventurer of "The Ghost Writer," "The Anatomy Lesson" and other novels.

That was 1983. Nearly 25 years and several more Zuckerman books later, Roth says he's really finished with his most enduring protagonist. "Exit Ghost," in which Zuckerman confronts old age and the decline of his powers, is, the author insists, the final word on the imaginary novelist with the Roth-like career.

"I think so," Roth says when asked if Nathan is gone.

Think so?

"I KNOW so," he responds, with a laugh. "I mean this to be conclusive, because that was my intention, and, as far as I know, my intentions are honorable."

From the beginning, like a rebellious child, Nathan has never turned out as planned. Roth first thought of Zuckerman back in the 1970s, when he frequently visited Eastern Europe and became a champion of such Communist bloc dissidents as Milan Kundera and Ivan Klima.

An idea arose for a novel: to juxtapose the fates of a Western writer and an Eastern writer. Roth wrote a first draft, 200-300 pages. It wasn't working.

"I thought, 'No, no, no, no. This was too much stuff for too little space.' So I took it apart, and first I wrote 'The Ghost Writer' (published in 1979) and finally worked my way down to 'The Prague Orgy,' " he says, referring to the first and fourth of his Zuckerman books, the first four of which were just reissued by the Library of America.

Like Roth, Nathan is a New Jersey native famous for a scandalous novel ("Portnoy's Complaint" for Roth, "Carnovsky" for Nathan). Both are Jewish liberals born in the 1930s (Nathan is 71, Roth 74). Their affinity is so strong that when Roth wrote a memoir, "The Facts," Nathan was given the final word, urging his creator not to publish the book.

"You are far better off writing about me than 'accurately' reporting your own life," Nathan advises.

The appeal of Nathan, Roth explains, is that "certain characters give you room to do certain things." You couldn't blame Nathan for wishing that someone else had the honors: He has suffered writer's block, impotency and the scorn of his family. In the mid-1990s, Roth kicked Nathan upstairs, restricting him to the status of "listener" in "American Pastoral," winner of the Pulitzer Prize and centered on the brother of one of Nathan's high school classmates.

"What happened with 'American Pastoral' was that I decided to give him (Nathan) prostate cancer," says Roth, interviewed recently at the offices of his agent, Andrew Wylie.

After minor roles for Nathan in "I Married a Communist" and "The Human Stain," Roth "thought it was over" again for his character. But as he began work on a novel about a man being treated for the effects of prostate surgery, he realized that man was Nathan, and the book became "Exit Ghost."

In "Exit Ghost," Roth allows Nathan to write his own escape, or at least lets readers believe it's Nathan wanting out. Nathan has met a young woman with whom he becomes infatuated. Unable to seduce her, he instead tries to write a fictional conquest, fails again and runs.

"Thus, with only a moment's more insanity on his part — a moment of insane excitement — he throws everything into his bag ... and gets out as fast as he can," Roth-Nathan writes.