Tracy K. Smith has had a successful career as a poet: her first two collections, The Body’s Question and Duende (Graywolf, 2003 and 2007), won major awards, and she began teaching at Princeton following her first book. When Life on Mars (Graywolf, 2011), her third collection, won the Pulitzer Prize, Smith skyrocketed to a level of fame that transcends the insular world of poetry—making now the perfect time for her to publish a book in prose. This month, Knopf publishes Smith’s fourth book, a memoir, Ordinary Light.

Ordinary Life begins with a harrowing scene at the deathbed of Smith’s mother, who died in 1994. From there it circles back to Smith’s early childhood, tracing her growth not just as a writer, but as someone who must learn the hard lessons of puberty and early adulthood, as well as what it means to be a black woman growing up in suburban California. Her discovery of poetry is part of this, but the most remarkable moments in this book are the ones in which Smith deals with ordinary trials, which she treats with rare insight and heart.

How long does grief take? Perhaps it takes a lifetime, in which case the real question is, how long does it take to begin? In two other recent grief memoirs (perhaps not coincidentally also by poets, for whom death is a perennial subject), grief hits hard and rapidly turns into writing—The Long Goodbye (Riverhead, 2011), by Meghan O’Rourke, and The Light of the World (Grand Central, April), by Elizabeth Alexander. In those books, the loss of a loved one—O’Rourke’s mother and Alexander’s husband—spurs a frenzy of pain, contemplation, and reevaluation. Both are transformative books that take a hard look at how grief plays out in contemporary America.

Smith is after something very different: her mother had been dead for several years when she wrote the first drafts of what would become Ordinary Light, and it was nearly 20 years before she began writing the book in earnest. This is not a chronicle of the shock of loss. Rather, it is a celebration of Smith’s life, lived in the thrall of a powerful, charismatic mother; it’s a chronicle of a big family with five children, and a story of coming of age amid deep and abiding love.

Though it opens with a deathbed scene, Ordinary Light sees Smith’s mother’s final moments as “the kind of miracle we never let ourselves consider, the miracle of death,” which opens the way to memory.

Smith was the youngest child in her family by almost a decade. Her mother was a teacher and then a homemaker, and her father was an engineer who worked on the Hubble telescope. The sense of being part of a tight-knit community within the household pervades the book and is one of its great pleasures: the reader feels invited to this love-filled home. Smith’s mother was passionately religious, especially after being diagnosed with cancer, and she tried to raise Smith as a Christian.

It took decades for Smith to finish the book, and she says it has its roots in much earlier work, from the years just after her mother died: “I tried to write some personal essays, some of which became the core of certain chapters in [Ordinary Life], as long ago as 1998. I just couldn’t finish them. I was kind of gripped with the same anxiety I had with the poems that I was writing at the time. The poems were trying to resolve this situation, which I later realized was an unresolvable thing. I didn’t have the proper distance.”

If pressed, many poets will admit that they have files of prose buried somewhere in their hard drives, which rarely turn into finished books. Smith was no different. “It was a secret project,” she says. “I never felt like I had to finish it. I would start something else.”

It took a fortuitous and unlikely honor to get this book going. It wasn’t winning the Pulitzer that did it; the book was well underway by the time Smith got that call. Instead, it was being chosen for the Rolex Mentor and Protégé Arts Initiative, a program run by the watch company that pairs a master artist with a younger one for a year of work on a project.

Smith was paired with Hans Magnus Enzensberger, the prominent German poet and prose writer. She says it was his help that “somehow gave me the courage and support to do the hard work.” Many young American writers tend to get tracked into one genre through M.F.A. programs, but Magnus, Smith says, “has no sense of boundaries between forms,” and his perspective helped her take her poet’s tool kit and expand it for prose.

She remembers how in early drafts she tried to get the prose to work the way poems do, using metaphors and descriptions to suggest feelings rather than creating scenes a reader could fully inhabit. “Images were doing all the punctuating work. I hoped they’d do the same thing they do in a poem, and it just wasn’t working,” she recalls. She had to ask herself a simple but challenging question for a poet: what does prose do? “It allows these different layers to accumulate. That helped. It got me out of what felt like an easy trick,” she says. Plus, she had been working on poems that dealt with her mother’s death around the same time as her first prose attempts, and she felt clearly that she “didn’t want to arrive at the same kinds of discoveries as in poems.”

That meant doing an entirely different kind of work: digging beyond the haze that time and memory can cast over events and attending to what really happened and what it might mean.

Smith says that she has never quite lost her mother’s sense of a higher power, though she’s had to come to it on her own terms. “I’m not unreligious,” she says, “but I don’t think the language I received is my language for what I’m praying to.” Smith’s mother struggled to impart her religious beliefs on her children while also allowing them to have ordinary childhoods. One chapter deals with Smith’s first Halloween of trick-or-treating. Smith remembers her mother saying, “As a Christian, I don’t think God is very happy on Halloween.”

She writes, “I wondered how one night of kids in costumes out trick-or-treating could bother God.” Her mother replies, “‘I know dressing up and getting candy is fun,... but what Halloween celebrates, things like evil spirits and demons, are the things of the occult. They belong to the devil, and they can be dangerous.’”

Yet Smith’s mother did hand-sew her a costume (an accidentally inappropriate one, a ghost that looked a bit too much like something else, making for a simultaneously adorable and painful episode in the book) and tried throughout Smith’s upbringing to take her daughter’s perspective and desires seriously, even when they didn’t mesh with her own religious views.

Expressing her conception of her faith was one of Smith’s motives in writing this book. She came to think you must “own up to what you think is real. I don’t think it’s easy to undo belief in a person, and I don’t know that I’ve ever really wanted to.” Though her own concept of God is different from her mother’s, she says that “the presence of a higher being is helpful.”

Another reason for returning to this material decades later was that Smith became a mother herself. When she returned to the book as a Rolex protégé, her daughter Naomi had been born (Smith now has three children). Smith was discussing her past with her husband, the poet and scholar Raphael Allison, and he said, “Write that book for Naomi.”

Smith’s brothers and sisters helped her in reconstructing the past and fully fleshing out their mother’s personality, seeing her not just through the eyes of a loving daughter but as a complete person with needs, desires, and fears of her own. She says her sister Jean, who lived with her mother at the end of her life, “was particularly helpful in clarifying the hazy spots.”

Writing this book has taught Smith that “memory rewards persistence,” and that the kinds of details that might naturally fall out of one’s consciousness began to resurface “when I sat down with the intention of remembering.”

That deep delving may have also helped Smith finally and fully grieve. “It brought my mother back in a way. It allowed those two different people—the me that was just becoming an adult—and her to be together in the same space. And just thinking about the things that I was and wasn’t able to say to my mother was a way of saying them.”