Alfred A. Knopf, 227 pp, $33.95, hardcover.

On December 30, 2003, American writer Joan Didion was mixing the salad when her husband, sitting across the dinner table, died. "I only remember looking up. His left hand was raised and he was slumped motionless." John Gregory Dunne, a fellow novelist and critic, had been with Didion almost every day since they married in 1964. They had worked together directly (they cowrote screenplays, including A Star Is Born) and indirectly, editing and reading each other's daily thoughts.

What follows is a year of questions, of Didion training her enormous intellect, her chilly probing gaze, on the difference between grief and mourning, between private (suffering) and public (performance).

There are no answers. "I could not count the times during the average day when something would come up that I needed to tell him," she writes. "This impulse did not end with his death. What ended was the possibility of response."

Yes, there are answers, answers Didion already knows. Powerless, we readers accompany her around and around the terrible details of Dunne's death (she requests emergency-room and autopsy transcripts; she's always been a good researcher), repeating the few facts and fewer meanings to compose some coherent narrative. The questions become a catechism, a framework that allows her to walk the terrain of death without getting lost in grief or madness. (Both seem possible.) They are not meant to yield new material; they are meant to ignite and feed a guttering faith in-not God, but coherence.

There's a lot missing from The Year of Magical Thinking, some of it private, some because Didion is a chronicler of surfaces; she has always presented large themes through the accretion of concrete specifics. (The technique has clearly struck a chord this time; Year has sold over 200,000 copies, won the National Book Award in November, and is being transferred to Broadway for 2007.) Missing, too, is the world of friends and family (alluded to, but not allowed on the page), particularly her daughter, Quintana Roo Dunne Michael, who lay in a coma as her father died and who wound up back in hospital repeatedly during this "magical" year. Missing, finally, is the resolution to Quintana's story, which you can find, once you've walked in Didion's resolute footsteps, by Googling her name and the date August 26, 2005.