IF YOU STAY UP LATE into the night to finish Wild, the 300-page memoir about a woman pushing herself beyond her physical and emotional limits, a woman who endured sore muscles, bruises, blisters, and soaring and plummeting temperatures, you will feel soft and lily-livered in the morning. If Cheryl Strayed can hike through California and Oregon in one summer, risking hypothermia, heatstroke, and death by any number of desert animals, one should be able, at least, to get one’s ass out of bed and perform some downward dog poses.

Wild is a memoir about Strayed’s solo hike over a thousand miles of the Pacific Crest Trail. With a keen eye for scene, character, and imagery, the author spins a masterful narrative infused wth the crackling of desert chaparral, and the aromatic pinesap of the Cascades. The empathetic reader may also feel every bruise, scrape, and muscle knot the young woman bears over the course of her expedition.

But Cheryl Strayed’s story begins far away from the Pacific Crest Trail, in rural Minnesota, on the “back-to-the-land” woodland farm where she grew up. In the wake of her mother's unexpected death from lung cancer, 22-year-old Strayed found herself unmoored, tumbling into common risky scenarios of the newly bereft: unprotected sex with strangers, infidelities, lies, and drug experimentation. As a result of this, her marriage eventually crumbled. Then her family scattered, having lost their mother, the nucleus that centered them. Strayed was plagued by nightmares in which her mother begged her to kill her. Within four years, she was orphaned, estranged from her brother and sister, and divorced from the man she married at nineteen.

After her life took so many unexpected turns, Strayed chose to do one more unexpected thing:

The Pacific Crest Trail was an idea, vague and outlandish, full of promise and mystery. Something bloomed inside me as I traced its jagged line with my finger on a map. I would walk that line, I decided—or at least as much of it as I could in about a hundred days. […] Each day I felt as if I were looking up from the bottom of a deep well. But from that well, I set about becoming a solo wilderness trekker. And why not? I'd been so many things already […] But a woman who walks alone in the wilderness for eleven hundred miles? I'd never been anything like that before. I had nothing to lose by giving it a whirl.

Strayed offers an image of herself as the inexperienced hiker who has never been backpacking, who weighs her pack down with so much needless gear (a foldable saw, an enormous camera flash, a fat roll of condoms) that she can barely lift it. Strayed recounts these early blunders with her characteristic humor and honesty. She does not self-aggrandize or gloss over, but admits plainly just how many times she came close to quitting (an hour into her hike, a day into her hike, the next day, the next few weeks). She shows herself whining, grumbling, wincing, and moaning. But as we follow the novice and her litany of mistakes — she uses the wrong fuel for her camp stove and buys too-small hiking boots that destroy her toenails — we witness her transformation into a seasoned and brave “Queen of the PCT” who can knock out twenty miles in one day and set up her tent “with a flick of her wrist.”

Most importantly, we see the hiker persevering. In the prologue, when her boots “sail irretrievably ...