Loss, nostalgia for a vanished past and “the unspeakable peril of the everyday” represented by “swimming pools, high-tension wires, lye under the sink, aspirin in the medicine cabinet” — these are the themes that have animated Joan Didion’s work, since “Slouching Towards Bethlehem” established her as one of America’s most distinctive and acute literary voices almost five decades ago.

All her fears about the precariousness of life were horribly realized in December 2003, when her daughter, Quintana Roo, went into a New York hospital with an apparent case of flu and was soon lying unconscious in an intensive care unit, suffering from pneumonia and septic shock; days later, her husband of 40 years, John Gregory Dunne, sat down for dinner and collapsed, dead from a massive heart attack. Quintana would die about a year and a half later at the age of 39.

Ms. Didion, now 80, chronicled these events in two books — “The Year of Magical Thinking” (2005), a shattering contemplation of loss and grief and sorrow, and “Blue Nights” (2011), a more elliptical meditation on her daughter’s life and death — much as she chronicled the rest of her life in her other work: her nervous collapses, her marital ups and downs, her anxieties, her illnesses, her craving for stability. In “The Last Love Song,” Tracy Daugherty — a fiction writer, and the author of critically acclaimed biographies of Donald Barthelme and Joseph Heller — unavoidably draws heavily upon Ms. Didion’s own writings while at the same time trying to draw distinctions between her real life and her literary persona, between her experiences as a daughter, writer, wife, and mother and what he astringently describes as her “working her brand.” He notes, for instance, that Ms. Didion wrote in “Blue Nights” about thinking of taking Quintana, then an infant, with her on assignment to Saigon, during the Vietnam War, implying that she was so unprepared to be a mother that the absurdity of such an undertaking never occurred to her. In fact, he writes, she was anything but clueless — “she was a steely professional, not about to let motherhood get in the way of her career.” What stopped her, Mr. Daugherty argues, was the simple fact that Quintana’s adoption had not yet been finalized and “she could not be transported out of state, much less out of the country.”

The Didion who emerges from “The Last Love Song” is both a frail, angst-ridden outsider and a shrewd Hollywood and New York insider; a vulnerable witness to history and a hardheaded survivor; a writer drawn to theatricality and extremes, and a woman who prizes order and control. Mr. Daugherty — who did not get Ms. Didion’s cooperation — does an agile job here of examining how his subject’s life illuminated the eras she traversed (and vice versa). He uses her experiences, much as Ms. Didion did, as an index of the cultural convulsions that rocked the country during the 1960s and ’70s, while at the same time, using her literary methods and musical sense of language to chart her peregrinations between California and New York, and her intellectual evolution over the years.

There are a few tasteless and superfluous lapses into gossip in this book — in one case, he even notes that a source’s observations “should be taken with heavy pitchers of salt.” And Mr. Daugherty dances nervously (though not as nervously as Ms. Didion has) around the subject of Quintana’s emotional difficulties and alcoholism, quoting a close friend who says her depressions and drinking were “probably intertwined” with her final illness (acute pancreatitis, which Mr. Daugherty writes, is “usually caused in young people by prolonged drug or alcohol abuse”). For the most part, this thoughtful and ambitious biography remains focused on Ms. Didion’s writing, using her life to shed light on her highly autobiographical work. Mr. Daugherty reminds us of the pioneer past of Ms. Didion’s family — her mother was a descendant of Nancy Hardin Cornwall, who, with her husband, had followed the ill-fated Donner-Reed party west, but split from the group in Nevada — and how this indelibly shaped her vision of California, and how California, in turn, became, for her, a metaphor for the promises and betrayals of America.

Over time, her nostalgia for a vanished frontier — the wagon-train mentality of its first settlers, the stoic individualism embodied by her beloved John Wayne — would mutate into something more ambivalent, an acknowledgment that selfishness and what she called a “mean scrambling for survival” had always lain beneath the romantic myths.

Although readers may not agree with all of Mr. Daugherty’s assessments of individual Didion books, his biography evinces a deep appreciation of her skills and idiosyncrasies, and an understanding of how writers like Conrad, Hemingway and her college professor Mark Schorer (who sharpened her awareness of textual nuances and the use of point of view) helped her forge her singular style. Mr. Daugherty expertly dissects Ms. Didion’s preoccupation with narratives — not just with the techniques of storytelling but also with the subtexts undergirding the personal and political story lines mapped in her work.

At the same time, Mr. Daugherty tries to tease out correspondences between Ms. Didion’s life and those of the heroines in her novels — most notably, anxiety over troubled or wayward daughters, from the emotionally impaired Kate in “Play It as It Lays” to Marin, the fugitive radical, in “A Book of Common Prayer” to the drug-addicted Jessie in “Democracy.” He suggests that Ms. Didion and Mr. Dunne’s focus on their own careers and self-absorption as writers sometimes sidelined Quintana when she was little (she was frequently parked with Ms. Didion’s parents, when they were traveling); that the Hollywood scene she knew as a teenager fueled her penchant for medicating her anxieties with alcohol and drugs; and that Ms. Didion was often in denial about Quintana’s problems. He is tough on Ms. Didion as a parent but arguably no tougher than Ms. Didion has been on herself (in print and in interviews) about her shortcomings as a mother, who missed or misread clues to Quintana’s unhappiness and screened off her worst worries and fears.

After finishing “Blue Nights,” Mr. Daugherty reports, Ms. Didion felt increasingly “weary, listless,” less inclined to push herself, less invested in maintaining the momentum she’d once prized, uncertain whether she would write again. Even her commitment to the pioneer imperative of stoicism and survival, he writes, had begun to waver. He quotes her saying to a friend, “There’s something missing in survival as a reason for being, you know?”