A number of good books in the last few years have toed the line between fact and fiction: they read like memoirs or autobiographies, but something pushes them into the realm of novel, whether it’s the implausible (as in Alice Sebold’s “The Lovely Bones”), the unlikely (as in Mitch Albom’s “For One More Day”), or simply a reconstruction of dialogues long gone. Usually, the publisher will help you out a little, labeling something as either fiction or memoir.

But then we come to “What is the What,” labeled as both the “autobiography of Valentino Achek Deng” and a “novel by Dave Eggers.” Eggers has toyed with us in this way before, taking extensive creative liberties in his bestselling memoir “A Heartbreaking Work of Staggering Genius.” Perhaps the better question in this moving new book about a Sudanese refugee isn’t What, but Which.

“This book,” writes the real Deng in the preface, “is the soulful account of my life: from the time I was separated from my family...to the thirteen years I spent in refugee camps...to my encounters with vibrant Western cultures.” Released two years after Colin Powell decided to crown the Darfur conflict with the term genocide, Eggers’ book is a story not of Darfur but of one of the thousands of Lost Boys—a term that, to many, has only some vague connection with both Sudan and “Peter Pan.”

A 475-page chronicle of a little-known life begs for a captivating beginning, and Eggers delivers just that. Deng’s story begins in Atlanta, where he innocently opens a door to a female stranger who promptly begins a dramatic robbery. Eggers weaves scenes from Africa into Deng’s account of the ongoing robbery with almost cinematic deftness. These first scenes also give the story a very human tension, making subtle (and not-so-subtle) comparisons, through Deng’s eyes, of Africa and America.

Deng confides that since coming to the States, he’s had a habit of telling silent stories to people who slight him—people whom he thinks would act differently if they knew the story of his suffering. Slowly but surely, Deng’s story unfolds through narratives he intends for various people who disappoint him in America. Everything from the happy, simpler days of Deng’s childhood to the horrors of the Lost Boys’ trek through the desert to his new life of adjusting to various American cities is subtly rendered and full of unembellished emotion.

Given almost constant exposure to the new and other media, I’m afraid to say I was shamefully desensitized to the accounts of brutal violence that are recounted in this story. Though I cried when Lightning McQueen pushed The King over the finish line in the cartoon movie “Cars,” I barely blinked or cringed while reading about a boy who was kicked to death in Ethiopia fighting over rations.

Eggers saves us, though, by recognizing that in our violence-saturated daily lives, what really brings the suffering home in this story and tugs at the heartstrings is not the gruesome descriptions of a brutal nightmare, but the shocking simplicity of Deng’s and his friends’ dreams, gorgeous fantasies of having children who will “speak English as Americans do,” the choice of different colors for shirts and shorts, bowls of oranges, or a bed of their own.

Inevitably, the decision to cast Deng’s story as a work of fiction comes into question, and one wonders if it somehow implies that the story wasn’t good enough to stand on its own, or whether focusing on just one man sacrifices enormity of the story of thousands of Lost Boys.Indeed, there are points where Eggers’ stylistic choices seem heavy-handed (on the 13th time that a transition into the past begins with the formulaic address to the hospital attendant, you wonder whether a simple line break wouldn’t suffice) and you long for a little artlessness.

But, in truth, Eggers’ retelling of this story is exactly what we needed. For those of us who have been reading new stories about hundreds upon hundreds of deaths, who are no longer shocked by another headline about a bomb in some distant city, and who have difficulty remembering (if we ever knew in the first place) who exactly the Lost Boys of Sudan were, this book gives us some of our heart back.

We’ll never need to scrounge around for those details because the tragedy comes alive with Deng. One of the plights of these boys, Deng tells us early on, is that they have been lumped into a single marketable identity.

Even they themselves, Deng admits, have merged their stories into the stereotype as they tell them over and over again. But, we are reminded, “[those] experiences were very different.” This is the crux of Eggers’ contribution: that he told the story not of the conflict or of the history of the Lost Boys, but of one man, and brought him to life.

—Reviewer Jessica A. Hui can be reached at hui@fas.harvard.edu.