"I knew you were going to ask me about that passage," she says, with almost a note of triumph in her voice. "I wrote that straight out of memory."

"So you didn't go back to the area for a refresher?"

"Oh, no, I've never gone back. The Tucson I knew doesn't exist anymore--you'd have to go to some rural part of New Mexico to get an idea of what it was like. But it made such a powerful impression. In fact, when I was writing those passages I had to call up Larry McMurtry, who's an old friend and an expert on the West, for some quick fact-checking. I wanted so badly for Maryna to see some saguaro cactus when she goes on that mystical hike into the void, because that's what happened on my first walk into the desert as a child. But Larry said, 'No, Susan, there are absolutely no saguaros in Southern California!' So that was that."

Even without their complement of cacti, the desert passages remain among the most lyrical of Sontag's career. "They had never felt as erect, as vertical," she writes, "their skin brushed by the hot Santa Ana wind, their ears lulled by the oddly intrusive sound of their own footfalls." Had she been looking for an opportunity to plug in this material?

"Not at all," she says. "Those memories simply rose up, unbidden, and I felt quite transported as I wrote them down. I actually thought, oh, this is a bit much, I should thin it out a little."

"The intensity makes sense, though. Your characters grew up in Poland, and could never have conceived of such a landscape."

"Of course," Sontag agrees. "Maryna and her companions come from a landscape that's saturated with memory, and with layers and layers of human occupation, and they're confronted by this emptiness . It's the kind of experience that changes you--that makes you capable of saying, 'To hell with it all! To hell with my wife or husband or child. I'll just keep walking.'"

On this nihilistic note, and with a similarly inconceivable landscape visible through the window--i.e., Hoboken, glittering on the opposite bank of the Hudson--Sontag leads me back to the bedroom, where she wants to dig out a book. Here, too, the walls are lined with bookshelves, from which she extracts a paperback edition of Leonid Tsypkin's Summer in Baden-Baden. "This is something you have to read," she says, and scribbles the title on a sheet of paper for me. Due, perhaps, to the proportion of books to other objects (a bed, a chair, an ectoplasmic-looking Tiffany lamp), this space strikes me as the most monastic yet: quite literally a reading room. It's clear that Sontag, who is now 67, is no less infatuated a reader or writer than she was when she published Against Interpretation nearly 35 years ago. But that's not exactly the rule among critics or novelists, is it?

"You're right," she says, "there tends to be a tapering off. I don't know why, and if I can think of any answers, they're going to be stupendously banal. Still, I do believe that people write, at least in part, out of their experience. And many writers seem to shut down with middle age, and worse: they get locked into their opinions and prejudices and crankiness and indignation. They conclude that old age is a kind of exile from experience."

"There are always exceptions, of course. I noticed you tipped your hat to Czeslaw Milosz in the Zero Chapter, and he certainly hasn't guttered out."

"Oh, yes," Sontag says, nodding her head and disarranging that steel-gray cascade of hair, now deprived of its signature white streak. "He's still terrific, a man of amazing spirit and dignity. And he's forgotten nothing! I love it when he writes poems about the power of eros. He may be 85 years old, but he still remembers it, even if--" She hesitates.

"Even if he's not personally involved?"

Sontag laughs. "That's right. But anyway, at the risk of sounding like a shameless self-promoter, I don't think I'm shutting down either. With these last two books, I actually feel like I'm in some early stage of my career, which is absurd given how long I've been publishing. My earlier work seems almost like juvenilia to me."

We're proceeding back down the hall to the living room, and I note that Sontag's carriage is strikingly youthful, given not only her age but a recent, second bout with cancer, which kept her on painkillers for months at a time. As we return to our seats, in fact, we pass a low table with a kind of medicine ball on it. "That's for physical therapy," she tells me, and plops down in the overstuffed chair again, resting her glasses on an adjacent stack of books. (The top one, somewhat appropriately, is Amazons of the Avant-Garde.) With a fired-up look on her face, she tells me that she went to the opera last night and cried at the end.

GO TO PAGE 4 OF "DESPERATELY SEEKING SUSAN"