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Title: “A Flame of Pure Fire: Jack Dempsey and the Roaring ‘20s.”

Author: Roger Kahn.

Price: $28.

When Jack Dempsey died at 87 in 1983, he took with him an era of American history.

He’d begun his life as a Colorado/Utah mining camp hobo, roustabout, miner, cowboy and whorehouse bouncer. Within a decade, he was the most electrifying sports figure in America.

Kahn captures it all and even provides some surprising conclusions in his biography of the man who drew boxing’s first million-dollar gates, despite the fact many Americans, who incorrectly believed he was a World War I “slacker,” detested him.

The sporting press in the so-called “Golden Age of Sports” comes out with a black eye. Kahn reports many big-name journalists of the day were on promoter Tex Rickard’s payroll.

In studying the two Dempsey-Gene Tunney fights in 1926 and ‘27, Kahn arrives at the startling conclusion that Dempsey, in the famous “Long Count” 1927 fight at Chicago, was done in by a dishonest referee, Dave Barry.

Because Dempsey wouldn’t obey a new rule, to go to a neutral corner after he’d decked Tunney in the seventh round, Barry gave Tunney an estimated 14 seconds on the canvas to recover while he ordered Dempsey to back off. But in the eighth round, when Tunney decked Dempsey for a two-count, Kahn writes, Tunney was permitted to hover nearby.

Kahn: “Two knockdowns, one round apart, and two different sets of rules. The explanation, I believe, is not complicated. In my tape of Chicago 1927, I am looking at a crooked referee.”