Mary Karr’s memoir follows two earlier biographical efforts, The Liar’s Club, the story of her upbringing as the daughter of alcoholics, and Cherry, about her unmoored adolescence and nascent poetic longings. Lit begins with Karr on her back porch with a tumbler of whiskey, a cigarette and headphones. Next to her is a monitor that lights up whenever her child coughs or cries. She is tied to reality only by the light of the baby monitor.

Roughly half the book chronicles the ruin of her marriage, the fumbling of her career and her attempt to keep her drinking to a minimum so that she can be a decent parent. Karr is an astonishingly good storyteller of self-made misery. Her tales of trying to be a Cambridge literary sophisticate while drinking heavily and being tethered to her parents’ ongoing calamities in Texas are strangely entertaining, at least for a while.

As her life disintegrates, Karr finds her way to an AA meeting in the basement of a church, where she momentarily sees through her own fog to recognize the fact of other people’s existence. Biting into a chocolate chip cookie, she briefly forgets “to feel sorry for [her]self, to worry, to generate any kind of report on [her] own performance.” This is the first inkling that there is a greater reality than the one she has embraced in alcohol.

Her recovery is held up by the fact that she cannot get her mind around the concept of a higher power. God is an all but meaningless word. When people at AA mention God, she hears her father’s voice in her head: “Higher power, my rosy red ass.”

A Harvard scholar who becomes her AA sponsor tells her to try praying. “No way, I say. Never happen, no offense.” A month later, she starts drinking again. Another person tells her that “faith is not a feeling. . . . It’s a set of actions.” Her first prayer, on her knees on a cushion in the living room while her son and husband sleep: “Higher power. Where the fuck have you been?”

Grudgingly Kerr begins to get down on her knees every morning and ask for help not to drink that day. At night she bends again to say thank you for a day without drinking. But prayer is still foreign. “What kind of god would permit the holocaust?” she demands of the poet Thomas Lux, who is also in recovery and is urging her to cultivate a sense of gratitude. “You’re not in the holocaust,” he replies. “Try getting on your effing knees tonight. Just find ten things you’re grateful for.”

Prayer does not save Karr’s marriage, and even when sober she ends up in a mental hospital for a time. But gradually she finds a different path. Prayer becomes “a space at the bottom of an exhale, a little hitch between taking in and letting out that’s a perfect zero you can go into. There’s a rest point between the heart muscle’s close and open.” This “vast quiet holds me,” Karr writes, “and the me I’ve been so lifelong worried about shoring up just dissolves like ash in water.”

Her son asks if they can go to church to “see if God is there.” Karr consents, and they begin a round of visits to churches, synagogues and zendos. She thinks that with her “half-baked sense of a higher power” she might resonate with “the super-liberal Protestant parishes that shun dogma.” But those churches seem sterile. When she asks one minister how he deals with the problem of evil, he says, “We don’t believe in it”—a phrase “so grotesquely untrue,” Karr remarks, “I wonder how they sell it.”

Eventually they find their way to a Catholic church, and Karr is so mesmerized by the mass that she forgets to take out her paperback. When her son hungrily goes forward for communion, she tries to draw him back, but she follows him. Eventually, she also follows him into classes to prepare for baptism. Karr’s account of her decision to be baptized contains the wry humor and inner wrangling that her readers expect. She still struggles with Jesus, the pope and the very idea of resurrection, but says “not choosing baptism would make me feel half-assed, like a dilettante—scared to commit to praising a force I do feel is divine solely from pride or because its mysteries are too unfathomable.”

Accounts of coming to faith can be saccharine or rely on cliché, but that’s never true in Lit. Sometimes it takes a “habitually morbid bitch,” as Karr calls herself, to articulate what that first glimpse of light in the darkness looks like.