In a scene from Barbet Schroeder’s 1987 film, Barfly, based on the life and times of Charles Bukowski, the protagonist, Henry “Hank” Chinaski (Mickey Rourke) has just been assaulted by his girlfriend, Wanda (Faye Dunaway), leaving him bleeding heavily from the head and all over his shirt. Someone knocks at his door and Hank answers, looking primordial. The man outside pauses, taking in his appearance, and asks: “Are you Henry Chinaski?”

“No,” Hank replies, “I’m Leon Spinks!”

A quarter-century ago, that line had rich comic recognition. Every viewer knew Leon Spinks. Neon Leon, they called him. He cut a memorable figure in pop culture—the missing front teeth, the superhuman partying and serial car smash-ups, the endemic and tragicomic inability to make sensible choices, the road to ruin pipedwith the sound of laughter, to paraphrase the Johnny Cash song, ringing in his ears.

In 1987, Leon was nearly a decade past his one crowning glory—February 1978, when he beat 36-year-old Muhammad Ali to win the heavyweight title in one of boxing’s great upsets. But no one was laughing at his younger brother, Michael. In 1985, Michael defeated the 36-year-old Larry Holmes to become the first reigning light heavyweight king to win the heavyweight crown. Michael and Leon thus became the only brother act in heavyweight title history (before the Klitschkos).

In One Punch from the Promised Land: Leon Spinks, Michael Spinks, and the Myth of the Heavyweight Title, John Florio and Ouisie Shapiro tell the story of these brothers who boxed differently, lived differently, and forged different fates (one lives in a mansion, the other doesn’t). The book is chock-full of fresh interviews and outrageous stories, and yes, most involve Leon. It also doesn’t skimp on frankness, whether acknowledging Leon’s mental deficiencies or Michael’s Marciano-like tightness with a buck.

The brotherly bond took form in 1950s and 1960s St. Louis, where Leon and Michael grew up in the nightmarish Pruitt-Igoe housing project. By the late sixties, criminal gangs ran the place, and police responding to crime calls wouldn’t enter without back up, which didn’t always come. Learning their trade at the nearby DeSoto Rec Center, the Spinks brothers fought their way onto the historic 1976 U.S. Olympic boxing team, which starred Sugar Ray Leonard and Howard Davis. Neither Leon nor Michael was expected to win gold medals, but both did. Leon turned pro. Michael went back to his regular job; he never loved boxing, but when Monsanto, for whom he worked cleaning offices, switched him to cleaning bathrooms, he thought he might like boxing well enough.

In the early going, the Spinks saga was all about Leon. In just his eighth pro fight, he was matched with an out-of-shape, unmotivated Ali, who by then barely did any fighting in the ring at all. He lay against the ropes, absorbing arm, shoulder, and kidney punches, looking to steal rounds, wear out opponents, and charm judges and fans with his clowning. The act had grown wearisome. Leon pounded Ali with abandon and held off a late-round charge to win the decision. The Greatest had been beaten by a novice pro. Moreover, he had been displaced as champion by a man as different from him as could be imagined.

Florio and Shapiro are insightful in describing how Spinks represented a new kind of heavyweight champion. Most of Leon’s predecessors came from poor or modest backgrounds, but none from such a deep-seated ghetto culture. He was “a kid from the projects who had little guidance, an eye for the ladies, and a sweet tooth for cocaine,” Florio and Shapiro write. “He had only two speeds—turbo and sleep.” Leon’s constant run-ins with the law for minor traffic infractions or drug possession—he was once busted for a quantity of cocaine valued at $1.50—made him a figure of ridicule within weeks of beating Ali. If it bothered him, he didn’t let on. To be certain, it bothered Michael, who put his own professional career on hold in a vain attempt to look after his older brother.

The authors describe how, shortly before it was time for him to enter the ring in New Orleans for his rematch with Ali, Leon disappeared, and neither his camp nor his bodyguard—Mr. T., the future Clubber Lang—could find him. He was finally located in a hotel room, drunk. Somehow Leon managed to fight on relatively even terms with Ali for five rounds before Ali took command. It wasn’t much of a fight. Ali danced for the first time in years, but he landed mostly one- and two-punch combinations while holding Leon ceaselessly over 15 rounds and winning a lopsided decision. Leon went back out partying and kept the party going for years, though his career quickly became a sideshow. He lost about as often as he won, drank up his paydays in single sittings, and generally lived the life of a wild, not terribly bright dude. Years later, training Leon for one last shot at remaking his career, Emanuel Steward went looking for the fighter and found him in the usual place—a hotel—and in the usual state—drunk, naked, and with a woman. “Coach, it ain’t like it look,” Leon said. Naturally, Leon wound up broke, and he shows signs of dementia today, but he is fortunate to have met and married a woman who is protective of him.

Where Leon was madcap, Michael was reserved and enigmatic, only slightly off-kilter and in none of the ways that make headlines. “Michael always seemed so logical compared to Leon,” promoter Bob Arum told the authors. “It seemed to me that Michael had some sense. Leon never had any sense.” Michael turned out to be a better fighter than his older brother, too, largely because of his personal stability and discipline. But in 1983, his life was upended when his common-law wife, the mother of his two-year old daughter, was killed in a car accident weeks before he was to fight Dwight Muhammad Qawi to unify the light heavyweight title. Just as he was preparing to enter the ring, someone brought the little girl into Michael’s dressing room. She promptly asked him where her mother was. Michael almost went to pieces, but he went out and beat Qawi, using his left jab to control the fight. Qawi derided him for “running.”

Michael had a curious ability to inspire disdain in his opponents, perhaps because of his unusual style, if it was a style. He’d start out orthodox, but in the heat of battle punches would start flying in from all angles. In 1985, when Michael beat Holmes—then 48-0 and one win away from equaling Rocky Marciano’s perfect record—Holmes complained about the decision, though Michael had won clearly. The following year, Holmes had a legitimate gripe about their rematch, which Michael also won by decision: most observers thought Holmes deserved the nod. Even in 1987, when Michael knocked out the much bigger Gerry Cooney, whom he feared, he couldn’t seem to convince his opponent. The usually gracious Cooney said that Michael didn’t belong in the same ring with him.

Where Leon endured a sustained descent, Michael’s downfall was mercifully brief: in June 1988, he faced off against Mike Tyson in the bout that would unify (for a few years at least) the heavyweight title. Tyson was at his peak, a terrifying force combining speed and power. Emanuel Steward told Florio and Shapiro that before the Tyson fight, Michael was afraid to leave his dressing room. He entered the Atlantic City ring, as the authors put it, wearing “the look of a rabbit that had just spotted a hunter’s rifle.” Michael’s trainer, Eddie Futch, wanted him to box Tyson, to stay away for four or five rounds—easier said than done in those days. “Take him out in deep water and then we can drown him,” he said. Tyson never gave them a chance, annihilating Spinks in 91 seconds. It was Michael’s only loss as a professional and his last fight. He lives on a generous spread outside Wilmington, Delaware, and mostly keeps a low profile. But he made news in 2011 when he sued the estate of the late Butch Lewis, his longtime manager and friend, for mismanaging the millions in boxing earnings that were to pay Michael’s living expenses.

“I don’t know what an average person goes through in a lifetime,” Michael once said, “but I’ve been through a lot up to now—and I have lived life as cautiously as I possibly can. My life hasn’t been a bowl of cherries.” Leaving aside the caution, Leon could say the same. Florio and Shapiro bring the Spinks brothers and their struggles to life and remind us that, different as they were, they were united by at least two deep forces: love and trouble. Consider a moment in September 1978 before the opening bell in New Orleans. As Ali stood in his corner calmly waiting for the fight to begin, Leon reached for his brother and held him in a tight, lingering embrace. He might have been voicing some version of the old spiritual’s lament: Nobody Knows the Trouble I’ve Seen. But Michael knew.