Norman Mailer didn’t set out to write a novel about Adolf Hitler.

“I was finally going to do the second volume of “Harlot’s Ghost” [his novel about the CIA] that I had been promising all these years,” he said, sitting on the top floor of his brownstone in Brooklyn with its expansive views of the Statue of Liberty and Lower Manhattan.

“I had an interesting notion that Harlot was going to be very interested in Carl Jung and that was going to be the intellectual vibration of the book. And then a week or two before I was going to start writing, it was as if another muse appeared in the doorway, crooked her finger, and said, ‘No, no, no. You come with me.” And I suddenly realized I wanted to write about Hitler.”

It wasn’t that the topic was new to Mr. Mailer, whose novel “The Castle in the Forest,” comes out this week.

“My Mother, who was fairly smart, was obsessed with Hitler,” he remembers. “Ever since I was nine she was talking about Hitler and how he was going to try and kill all the Jews. Even when the so-called experts were talking about how Hitler would mature, she knew otherwise.”

Mr. Mailer, who was nine in 1932, says that the work of one man deserves credit above and beyond for spurring him on: Ron Rosenbaum, author of “Explaining Hitler.”

“The book,” Mr. Mailer said, “stimulated the hell out of me, absolutely knocked me out when I read it. My mind began to race with all the possibilities about Hitler and at a certain point, I finally realized I had a lot to say about Hitler.”

Mr. Mailer points out that there hasn’t been a lot written in English about Hitler’s youth, which gave him an opening.

“There was some real room to write a novel there,” he says. “And then I got the real happy notion to have a devil write it. And, after that, it was just a matter of writing for a couple of years.”

One part of the book that has attracted attention Mr. Mailer hadn’t expected is the bibliography he includes at the end.

“I don’t know what got everybody so upset about,” he said. “It seemed like the perfectly decent, natural thing to do. You’ve read all these books why not give the people who wrote them, if they happen to come across the bibliography, the pleasure of seeing their name in print. What’s so terrible about that?

“I wasn’t saying, look at me, I’m a serious writer. I take it for granted that I’m a serious writer.”

As for other serious writers, Mr. Mailer knows they are out there (“I hear Dave Eggers is wonderful,” he said), but doesn’t read nearly as much as he used to.

“I almost don’t read anyone anymore,” he said. “The older I get, the more sensitive I’ve become to good writing. It stimulates me immensely, and then I go off in all sorts of directions thinking about how I would’ve done it. And my mind races and it distracts me from my own work. And so I rarely read a good writer anymore.”

As Mr. Mailer talks, he is faced away from the window with its stunning views: a concession, he said to old age.

“My eyes are giving out, one of the reasons I don’t read as much,” he says. “And the light bothers me tremendously.”

While Mr. Mailer isn’t able to enjoy the view as much as he used to — he now only spends about 20 days a year in New York and considers Provincetown his primary residence — he still thinks of himself as a New Yorker.

“Spiritually, I’m a New Yorker,” he said. “I always have been, I grew up in Brooklyn, after all. If you grow up in Brooklyn, you’re a New Yorker ipso facto.”

Mr. Mailer said as much as he loves New York, it’s no longer the best place for him.

“It’s a two-sided issue. On one hand, I absolutely miss New York,” he said. “On the other hand, I’m too old for it. It used to be that my wife and I could go out for dinner, stay out, and I’d get up the next morning and work. If I’m out at night these days, I’m no longer ready to work the next morning.”

Not only does Mr. Mailer describe himself as a New Yorker spiritually and historically, he once ran for mayor with columnist Jimmy Breslin as his running mate.

“Looking back on it, there was something highly comic about the whole thing,” he said. “Not at the time, of course. Breslin and I worked as hard as we ever worked. One of my favorite remarks at the time was that my mother didn’t raise me to work this hard. The press thought it was a lark, but it wasn’t a lark. It was a bone-depleting journey.”

“What is comic about it, what I find comic about it, was how little political sense I had compared to how much political sense I thought I had. What I didn’t understand was that a freshman doesn’t run for president of the fraternity.”

Mr. Mailer said that Senator Obama of Illinois shouldn’t read too much into that.

“While I was very proud that I came up with that after the election, of course, soon after, Jimmy Carter comes along, and he’s a freshman, and he gets elected president. “So, of course, one of the rules of politics is that there are no rules.”

As for Senator Obama, Mr. Mailer said that he hasn’t followed him too closely but that since “everyone is so enthusiastic about him, my feeling has been just to sit back and wait. He might be very good. He might not. The true test is going to be now that he’s going to run he’s going to have to make statements and people are going to be coming to him and going away from him.

“And that’s where the art of the politician comes in. Can he make statements in such a way that more people come to him than go away from him.”

As for one of Mr. Obama’s anticipated major rivals — Senator Clinton — Mr. Mailer said “she’s probably earned the job as much as anyone on the Democratic side.

However, he adds, “She has that funny publicity problem. Personally, she’s charming, but that’s not the public perception of her. And I don’t know how you overcome that.”

One the Republican side, Mr. Mailer sees Senator McCain as “formidable” but warns Mr. McCain to expect to see what he calls the “ugly, very ugly” picture of him embracing President Bush used widely against him. But, Mr. Mailer says, he doesn’t know if the Democrats would use it.

As for Mr. Bush, Mr. Mailer does not have kind words, referring to him as “nasty and stupid.”

Mailer also said that Mr. Bush, whom he believes is “not deep enough to be evil,” is a “social phenomenon,” the product of a shopping, marketing-oriented society.

“People believe that buying things is one of the most significant acts they can take, and that is the handmaiden to stupidity. The country has become more and stupid over the past 15 to 20 years, and George Bush is the fruit, the flower, of that tendency.”

Despite his misgivings on the country’s intelligence, Mr. Mailer is not entirely pessimistic. After all, he does dedicate his new novel to his grandchildren, an optimistic sign.

“I am a pessimist with occasional optimistic tendencies,” he said. “I tend to be a pessimist. That way when I get good news, I’m more uplifted. If you are start off as an optimist, you find yourself more easily disappointed.”

Mr. Mailer — whose life has included an incident in which he stabbed his wife and a controversy over a person he helped get out of prison who then committed a murder — said that while he has regrets “they are not something I discuss publicly.”

One regret he does not have is losing the race for mayor in 1969.

“The city went bankrupt soon after, and if Jimmy and I had won, they would have blamed us,” he said. “It’s like we had a guardian angel watching over us. While at the time, we thought we were walking into bullets, it turns out we were dodging a big bullet.”

And, for now, Mr. Mailer has his work to keep him busy.

“Work more important than anything,” he said. “It’s onerous in one’s middle years but a blessing when you’re old.”

Mr. Mailer said one project he once very much wanted to finish was a trilogy of books, of which only the first one ever got written.

“Ancient Evenings” was supposed to be part one of a series that dealt with the past, present and future. It was the third book that brought an end to the idea. It was to be set on a spaceship with a few select humans, with Earth no longer around, looking for a new planet.

“I realized I no longer had the mental equipment to tackle science fiction.”

In the meantime, Mr. Mailer says, he hopes to write a second novel about Hitler.

“I’m not going to promise it because at my age you can’t. If I last long enough there will be a second volume.”

As for the sequel to “Harlot’s Ghost,” the book he promised to write but from which he got diverted to write about Hitler?

“I’m afraid that’s one promise I won’t keep,” he said.