The body artist of the title is Lauren Hartke, who does conceptual performance art pieces in which she systematically transforms her body on stage in various ways. She's suddenly lost her husband, a self-invented Spanish film director named Rey Robles. In a short, lovely opening set piece, DeLillo presents us with a moment-by-moment account of their final morning together: She can't stop sniffing the box of soy granules, trying to figure out what they smell like, as he half-answers her questions and they share the newspaper and turn the radio on and off.

We soon learn of Rey's death by reading his obituary, and the rest of the novel scrutinizes Lauren's inner world during the first few months of her grief. She discovers that a mysterious, childlike, half-insane homeless man has been living in the ramshackle seaside house the couple has been renting, and he freaks her out by repeating snatches of her conversations with Rey over the past months. As she holes up in the house, avoiding answering the phone and trying to figure out how to relate to the strange little man, it's almost, but of course not really, as if Rey is still there with her.

That's about it, as far as plot goes. What keeps the book going are the big philosophical questions that Rey's death raises for Lauren, questions she explores in a body art piece she's working on. They're self-consciously profound, and as likely to alienate nuts-and-bolts readers as to exhilarate more theoretically minded ones: How do we experience time? How do we know what "reality" is? The chapters drift elliptically from idea to idea, just as Lauren spends these months wandering in her own mind, kept company only by the enigmatic intruder she calls "Mr. Tuttle," a person she never quite figures out: "Time is supposed to pass, she thought. But maybe he is living in another state. It is a kind of time that is simply and overwhelmingly there."

DeLillo includes in the novel a journalist's description of a show Lauren performs called "Body Time": "Hartke clearly wanted her audience to feel time go by, viscerally, even painfully," it reads. "This is what happened, causing walkouts among the less committed." Like his heroine, DeLillo knows that the kind of abstraction he's purveying is difficult and even boring, but that's his point. If anyone has earned the right to bore us for our own good, it's DeLillo. Be brave enough to be inside your own head, he suggests; there's a level on which your memories, your dreams, your regrets are real -- they take up space in your head and in your days.

"Is the thing that's happening so far outside experience that you're forced to make excuses for it, or give it the petty credentials of some misperception?" DeLillo addresses this challenge directly to his readers at the end of the book, as Lauren finds herself in a scarily lifelike reverie about Rey. "Is reality too powerful for you?" Is it?

Maya Angelou reads from "The Heart of a Woman"