Before the full catastrophe of life struck her broadsides, the writer Joan Didion led a shining, privileged life. She was one of the most admired American writers, reporting in novels and literary journalism from the center of the national story. Her beloved husband, John Gregory Dunne, a highly-regarded writer himself, was her most trusted confidante and collaborator. An already inseparable couple, they looked forward to spending even more time together as they grew older. Their only child, Quintana, had negotiated the rapids of adolescence and was now grown up and married.

Then, famously, disaster struck. Within less than two years, her husband and daughter were dead. At seventy, Didion found herself alone. Her flinty self-reliance faced its stiffest test. Would her old pioneer code of “bury the baby and keep going” be sufficient? There to witness how Didion found her way was the writer Sara Davidson, the author of the best-selling Loose Change. She and Didion met in 1971 when Davidson, then a young reporter, phoned her idol, looking for wisdom on how to live as a woman and a writer. Didion invited her to supper, and so began a friendship that has lasted forty years.

It’s a friendship with its share of amusing moments. At a Hollywood party, Davidson witnessed Didion reject an overture from Warren Beatty, then at the height of his womanizing powers. “This is all I want, right here,” he told Didion, staring into her eyes. “I don’t have to be on the set until ten Monday morning.” “This is not…feasible,” Didion responded, smiling shyly.

Over the years, Didion and Davidson compared notes on marriage, men, parenthood, and careers. But most of all, they talked about writing, with Didion sharing more than four decades worth of insights acquired as far back as Slouching Towards Bethlehem (1968) and as recently as Didion’s newest work, Blue Nights (2011).

Joan is a loving, intimate portrait of a deeply private writer. It is a treasure trove of Didion’s no-nonsense wisdom about the art of literature and life, and about the power of endurance—and now, surrender. Although Didion says she has gotten no wiser with age, Joan belies that.