Distinguished American writer Joan Didion has always seemed delicate, but now she looks frail. Her shoulders are thin and stooped as she speaks haltingly about the loss of her daughter a few weeks ago, as she was still grappling with the sudden death of her husband on Dec. 30, 2003. Her weight has dropped below 80 pounds, and her pants and pullover hang loosely from a 5-foot-1 frame that now seems perilously thin. She seems dwarfed by a living room filled with art and mementos.

As she notes at the beginning of her new memoir, "The Year of Magical Thinking," which goes on sale today, "Life changes fast." The book is , about the year following the death of her husband, the writer John Gregory Dunne, of a heart attack just a few weeks shy of the 40th anniversary of a marriage that was a legendary creative partnership. It was going to press when, on Aug. 26, her daughter, Quintana Roo Dunne Michael, a photographer and photo editor who had been hospitalized since June, died at 39 after a long series of illnesses.

As she prepared last week for her daughter's memorial service on Thursday at New York's St. Vincent Ferrer Church, Didion seemed suspended in raw grief.

"You feel fragile," she began, taking a seat in front of a fireplace, her eyes dark and bright, her voice soft. "For a while after somebody dies you can't eat. I'm trying to eat again. I've lost 5 pounds. I [now] weigh in the 70s, so 5 pounds is a real issue. My friends call. They remind me to eat. It's sort of embarrassing. We should all be able to take care of ourselves."

"There's a point when someone dies that you just can't stop the outbursts of crying," she said. "Then there's a point where you just live with it. It's an absence rather than a condition."

If she didn't try to carry on right now, she said, "I would feel guilty. Was I reentering life? There's a certain obligation to live your life."

"That's one reason I'm going out on the road" to promote the book, as she had planned before Quintana's death, she said. "It's part of learning to live with it."

"I think it'll be her salvation," said her agent, Lynn Nesbit. "That might be too strong a word, but I hope it will be good therapy. Work is a safe haven for her."

The silent rooms of the apartment seem a minefield of memories.

Here are the photographs of Quintana as a wide-eyed baby. Here she is as a little girl wading in the sea in Malibu, as an early adolescent with long blond hair and a suddenly direct gaze that hints of adulthood to come.

Here is the living room where, at Didion's annual Easter gathering of family and friends, Quintana asked her husband, Gerry Michael, to help her get up from the wheelchair her illness had caused her to use. She walked from the door to the sofa.

Here is the small table where, in "The Year of Magical Thinking," Didion describes how Dunne collapsed from a heart attack in the middle of a conversation about World War I or scotch, she can't remember which. Here is the living room that paramedics turned into a triage center, spilling blood onto the floor, just a few feet from the white slip-covered furniture, the delicate toile pillows and the clouds of papery white moth orchids that float over terra cotta pots on a table at the entrance of the still apartment.

"It isn't like when John died, when there were a lot of people there," writer Calvin Trillin, a friend of Didion and Dunne, said of the days following Quintana's death. "I think this time she wanted to do it more by herself. Somebody told me there's an African blessing, 'May we be buried by our children.' It's obviously the hardest loss."

The apartment seemed warm and humid, but Didion felt a chill -- "If you weigh under 80, you tend to get cold" -- and pulled on a soft pink sweater. When you are grieving, she said, "you feel very fragile, physically fragile, for no reason. Maybe you are more fragile because you're under stress. I got pneumonia in May for no reason."

She walked down a hall papered with framed pictures of Quintana: "Anyone who is not objectionable about his daughter is a pervert," read a quote attributed to Franklin Pierce at the center of a photo montage of Quintana hanging by the his-and-hers studies where Didion and Dunne talked across the hall throughout the day.

If Dunne heard an interesting anecdote on the telephone, friends say, he would call out, "Joanie, pick up the extension," so she could hear the story too.

"They were together 24 hours a day," said Nesbit, a longtime close friend of the couple. "They were truly each other's best friend. It's quite heartbreaking to see that picture on the back of the book of the three of them together and look at Joan today. Grief is etched all over Joan's face."

In Didion's study, a game of computer solitaire glows on the green screen of the laptop on her desk. A shelf nearby holds a picture of a previous Joan Didion, a young woman with a deadly serious gaze that seems at odds with the glamour of the large dark sunglasses she typically wore and the fascinating life she had earned. Nearby is a photo of Quintana, a little girl in a washed-out sundress, a few inches from a book called "Baby Animals and Their Mothers."

Another pile of books near the desk deals with the matter at hand: "For the Bereaved: The Road to Recovery," "The House of Death," "Grief Counseling and Grief Therapy" and an academic tome, by Sherwin B. Nuland, called "How We Die."