Joan Didion has been many people over her 76 years: journalist, wife, novelist, mother, widow. To each role, she has brought her singular gift as an observer of lives.

“Life has taught me that if you sit there at the typewriter, eventually, something will come through,” she explains by phone from her New York apartment, where she relocated in 2005 from her longtime home in Los Angeles.

In recent years, several difficult events have tested that easy relationship with writing — and revealed that Didion’s most compelling subject now is herself.

In many ways, Didion’s output — 40 years of essays, books and screenplays — is the story of boomer America. She pioneered the New Journalism style of narrative nonfiction with 1968’s “Slouching Towards Bethlehem,” notes on life at the edges of California ’60s counterculture. In her novels, falling-apart starlets, Vietnam vets and slick politicos embody the anxieties and aspirations of their successive epochs.

Didion’s previous book, the bestselling 2005 memoir “The Year of Magical Thinking,” came out of a sudden tragedy: Didion’s writing partner and husband of 40 years, John Gregory Dunne, died at the dinner table one evening in late 2003. Before that, the couple had been dealing with the protracted illness of their adult daughter, Quintana Roo Dunne. Quintana’s health continued to decline over 2005 as Didion toured for “Magical Thinking,” which won the National Book Award that year.

Quintana died in August 2005 at the age of 39. Didion’s new memoir, “Blue Nights,” plots the author’s passage on the terrible journey that began then — from being the mother of a child to being a mother who has outlived her child. And though the book is about grief, it is more transformative than depressive.

“This book didn’t tell me what it wanted to be until I decided to call it ‘Blue Nights,’” she says. “I thought it was going to be much less personal — more about people and children in a researched way and much less about me and my child in a contemplative way.”

Didion says the act of writing — a process that brought order to the turbulent events of all those previous eras — allowed her to manage and comprehend this new loss.

“Writing turned out to be tremendously useful to me in a certain way,” she says, “because I was formulating thoughts about things that I had been unable to consider in any way. By writing them down, I gradually came to live with them.”

On Her Next Book: “I started making notes for another novel, but since John died, I haven’t actually looked at them. Quintana was sick, and I was wrapped up in what was going on. I still have the notes in a box under my desk, and it may be that this spring or this summer I’ll take them out. But I don’t know exactly what I feel like doing next.”

On the Resonance of ‘A Year of Magical Thinking’: “I realized that the people who were talking to me about it were reading it not as being about the death of my husband or the illness of my daughter. They were reading it, in a sense, as a love story. They were reading the part of it that was about what appeared to be a satisfactory marriage, until it ended.”

Joan Didion: A Primer

Selected works from the author’s long and varied career.

Slouching Towards Bethlehem (1968, nonfiction): Didion’s best-known collection of essays chronicles life in ’60s California, covering Haight-Ashbury, John Wayne and the era’s shifting morals.

Play It as It Lays (1970, fiction): An actress copes with her daughter’s mental illness and her own harrowing abortion in Didion’s second novel, which Time included on its recent list of the top 100 modern novels.

A Star Is Born (1976, screenplay): Didion and her late husband changed the backdrop of this previously adapted tale to life on the rock ’n’ roll road, creating a star vehicle for Kris Kristofferson and Barbra Streisand.

The White Album (1979, nonfiction): Didion muses on the Doors, the Manson family and her own attempts to “freeze the shifting phantasmagoria which is our actual experience.”

Democracy (1984, Fiction): Blurring distinctions between herself and the narrator, Didion deftly blends fiction and journalism in this tragedy about the wife of a U.S. senator who has an affair with a CIA agent.

Political Fictions (2001, nonfiction): Didion examines the echo chamber of politicking and the political press through the lens of a decade of presidential races.

Where I Was From (2003, nonfiction): Didion’s most sustained exploration of the culture and history of her home state of California, where land and water are the most valuable currencies.

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