As a child, Cassius Clay used to stand in the space between his family's home and the house next door and urge his little brother to throw rocks at him. "Rudy threw as hard as he could while his older brother jumped, ducked, and darted," writes Jonathan Eig in "Ali: A Life," his stunning new biography of the three-time heavyweight boxing champion.

Eig does not say that those early years of ducking and darting led to the boxer's later skill at dodging and dancing in the ring. A reader might make that link, but Eig is far too precise of a biographer to draw conclusions based on conjecture. He lets the details of the story speak for themselves — and he has a lot of details, and a lot of stories. "Ali" is a big, fat, entertaining and illuminating read.

Much of the story of Muhammad Ali (born Cassius Clay Jr.) is widely known. Some of us remember his life unfolding on television; others grew familiar with him when he lit the Olympic Torch in 1996, his arm trembling from Parkinson's. There have been many biographies, full and partial, including one published in May.

What makes Eig's book stand out is its broad scope, its detailed reportage and its lively, cinematic writing.

Eig conducted more than 500 interviews for this book, examined FBI files on Ali and unearthed a trove of taped interviews that Ali had done with Sports Illustrated when he was still Cassius Clay. "Those recordings … were like time-travel machines," Eig writes, "getting me as close as I could ever hope to being in the same room with young Cassius Clay."

The Ali that emerges from these pages is a familiar one — gregarious, charming, funny, boastful, trusting and generous. He was not well-educated (he suffered from severe dyslexia), but he was smart and confident. He knew quite early who he was and what he wanted. He was a self-promoter long before self-promotion was a thing. As a teenager, "he began knocking on doors before his Friday night fights to stir up interest and boost attendance," Eig writes. "No one told him to do it, and it was completely unheard of at the time."

Above all, Eig portrays Ali as a man profoundly shaped by race — by his early awareness of the unfair treatment of blacks in the United States and by the teachings of Malcolm X, Elijah Muhammad and the Nation of Islam, which inspired him to change his name and refuse the draft.

Ali was raised in a middle-class, two-parent home in Louisville, Ky., just down the street from Fontaine Ferry, a year-round amusement park for whites only. Ali and his brother Rudy "could hear the rattle of the roller-coaster cars … smell the overcooked grease and fried dough." But they could not go inside. At night, the young Ali "lay in bed crying, asking why colored people had to suffer so."

He grew up a man of contradictions — deeply concerned about racial equality, but silent on the Freedom Riders and the Rev. Martin Luther King Jr. Profoundly religious, but a serial philanderer.

Although race is a crucial theme, it is boxing that is at the heart of this book. The fight scenes are beautifully wrought — vivid and detailed, rich with description and metaphor. Ali "fought like a bomber jet rather than a tank." George Foreman had "a punch that could coldcock a rhinoceros." The atmosphere of the boxing arena had "cigarette and cigar smoke draping the air, the shouts, the moans, the voices screaming for holy blood."

Ali's later fights, after he had gained weight and slowed down, were little more than endurance matches. He could no longer dance and bob but instead lay against the ropes accepting the punches, deploying the rope-a-dope, hoping to wear out his opponent and not fall down. He fought long after he should have quit, long after the effects of so many punches to the head became apparent.

Eig's research into the effects of head trauma make those scenes particularly excruciating to read. If Ali did not understand the damage that was being done, the reader most certainly does.

In the early years, however, Ali was a bold, confident original: a brash, proud black man born during the time of Jim Crow who refused to play the part of a "good Negro."

"Some writers said that Ali had 'transcended' race," but that was "dead wrong," Eig says. "Race was the theme of Ali's life. He insisted that America come to grips with a black man who wasn't afraid to speak out, who refused to be what others expected him to be. He didn't overcome race. He didn't overcome racism. He called it out. He faced it down."

Ali was the embodiment of America, Eig writes. "Big, beautiful, fast, loud, romantic, crazy, impulsive. … The most beautiful heavyweight of all time."

Laurie Hertzel is the Star Tribune senior editor for books.

Ali: A Life
By: Jonathan Eig.
Publisher: Houghton Mifflin Harcourt, 623 pages, $30.