Emmett Till's grave marker in Alsip, Ill. (Robert A. Davis/Chicago Sun-Times via Associated Press)

Leonard Pitts Jr. is a nationally syndicated columnist for the Miami Herald and the author of the novels “Freeman” and “Grant Park.”

Everyone already knows the story. It is like some grim fairy tale of the unreconstructed South.

Everyone knows how a 14-year-old black boy from Chicago named Emmett Till went to Mississippi to spend the summer of 1955 with his family. Everyone knows how he wolf-whistled at a pretty white woman, how he was kidnapped by her husband and his half-brother, how he was butchered and dumped in a river. Everyone knows how his body rose to the surface three days later, how his grief-stricken mother, Mamie Till-Mobley, insisted upon an open-casket funeral so the world could see what America had done to her child. Everyone knows how his killers were set free. And everyone knows how the murder galvanized an outrage that had long lain simmering in the collective breast of African American people, how it was said to be one of the reasons an Alabama seamstress named Rosa Parks said no when a bus driver in Montgomery demanded that she surrender her seat four months later.

Everyone knows the story. And that’s the biggest challenge Timothy B. Tyson faced in recounting it. A story often told has a way of growing smooth and featureless in the telling, of losing the blood, heat and immediacy that made it worth telling in the first place. And if any story deserves better, this one does.

So the most valuable service Tyson, a Duke University visiting professor and author of “Blood Done Sign My Name,” renders in “The Blood of Emmett Till” is simply to clear away the underbrush of myth that has accumulated over the decades and restore the immediacy of this quintessentially American story. He accomplishes this feat over the course of just 218 swift-flying and meticulously researched pages, bringing the story back to vivid life with a journalist’s nose for facts and a novelist’s eye for telling details.

Carolyn Bryant in 1955. (Gene Herrick/Associated Press)

So you get not just the hard fact of the half-brothers, J.W. Milam and Roy Bryant, showing up at the door of Emmett’s sharecropper uncle, Moses Wright, in the middle of the night but also the heartbreaking image of Wright standing alone in his yard, watching long after the kidnap vehicle, its headlights doused, has melted into the shadows.

You get not just the hard fact that the body was discovered three days later but also the odd, misplaced priorities of the teenager who saw the dead boy’s knees and feet poking out of the water while walking beside the Tallahatchie River just after dawn, yet took time to check his trout lines before alerting authorities to his grisly find.

You get not just the hard fact of Wright committing the unthinkably brave act of testifying in court against two white men but also the indelible truth of what it must have felt like to be Moses Wright in that defining moment, sitting there in his neat white shirt and black pants, his fingers tugging nervously at one another as cigarette smoke rose toward the ceiling fans in a crowded courtroom hot as an anteroom of hell.

And you get not just Emmett Till, the human cautionary tale whispering his warnings across six decades, but Till as he was in life, a brash, fun-loving boy who sang street-corner doo-wop badly and loved Jack Benny.

Tyson’s book could not arrive at a more propitious time. Ever since the stalking and killing of Trayvon Martin by a self-deputized neighborhood watchman in 2012, this country has been riven by renewed debate over the American habit of destroying African American life. A cry arises from African Americans and their allies that “Black Lives Matter,” and the rest of the country responds with contrived confusion and feigned ignorance, professing not to understand why such a thing is necessary to be said.

The answer, of course, is as obvious as a chimpanzee in church. Namely, that when African American lives are destroyed by white people, America has historically been reluctant to bring the perpetrators to account. That was famously the case with Till. And with Martin. In that sense, Emmett was Trayvon was Abram Smith was Thomas Shipp was Sam Hose was Rubin Stacy was Eric Garner was Tamir Rice was Mary Turner was Jesse Washington was Laura Nelson was Prince Jones. And on and on. Our history is a seething river of unpunished blood.

So “The Blood of Emmett Till” is a work critical not just to our understanding of something that happened in America in 1955 but of what happens in America here and now. It is a jolting and powerful book.

(Simon & Schuster)

But it might have been even better.

Perhaps the most important thing Tyson achieves here is to bring us the voice of the former Carolyn Bryant. Now an octogenarian, she has kept a six-decade public silence about that late-summer day in 1955 when a black boy got fresh with her. Like “the white man,” the otherwise unidentified individual whose need for a bus seat propelled Parks into immortality, Bryant was a hinge upon which history swung. Like him, her absence from the subsequent record has always made her seem less a flesh-and-blood person than a plot device employed by history’s author. In breaking her silence in the pages of Tyson’s book, Bryant makes herself finally real, filling in the blanks of her and her then-husband’s lives before and during that awful summer.

And yes, as reported in recent headlines, Bryant also recants a claim she made at the time that Emmett put his hands on her, first seizing her wrist and then grabbing her about the waist. Those headlines treat that news as arguably more significant than it is. After all, the accusation of physical contact, while it roiled the South in 1955, is scarcely recalled 62 years later. What has survived into the modern era, what remains the crux of the story, is Bryant’s claim that Emmett said something untoward in their brief encounter, and she doesn’t quite recant that, though she says she can no longer exactly recall what that something was.

“I want to tell you,” she tells Tyson. “Honestly, I just don’t remember. It was fifty years ago. You tell these stories for so long that they seem true.”

Meanwhile, she never gives you the one thing you want most: the satisfaction of seeing her grapple with her role in history. What is it like to be “the white woman” who helped destroy a child? How does it feel to know that what you did and what you were stand rebuked? How do you live with having been so monstrously, catastrophically wrong?

Bryant never says.

Maybe Tyson never asked her, which would be a lapse of reportage. Maybe he asked and she could not answer, which would have been important to know. Whatever the reason, the reader never really sees Bryant struggle with these things — and that is disappointing. To struggle with them is the very least she owes the memory of Emmett Till.

There is a small moment, though, when Bryant unburdens herself of an admission that any person with a spark of decency would consider self-evident.

“Nothing that boy did,” she tells Tyson, “could ever justify what happened to him.”

It hardly satisfies the need to see her wrestle with what she did. But it is, perhaps, the best she can do, even now.

The Blood of Emmett Till

By Timothy B. Tyson

Simon & Schuster. 291 pp. $27