Michael Bloomberg was just a year old when, in 1943, the author Esther Forbes published a children's novel, "Johnny Tremain," the tale of a young Revolutionary-era silversmith apprentice in Boston on the eve of war. The book would come to dominate Bloomberg's imaginative life. As a boy growing up in Medford, Mass., he recalls, "I must have read it 50 times." In the great rhetorical scene at the heart of the story, the revolutionary James Otis addresses a small tavern gathering that includes Sam Adams, John Adams and John Hancock, reminding the nascent rebels that their fight is not only national but global. America would make war, Otis said, so that "there shall be no more tyranny." Between deep sips of grog, he went on: "The peasants of France, the serfs of Russia. Hardly more than animals now. But because we fight, they shall see freedom like a new sun rising in the west. Those natural rights God has given to every man, no matter how humble … We give all we have, lives, property, safety, skills … We fight, we die, for a simple thing. Only that a man can stand up." A few moments later, the meeting over, Johnny, who would ultimately be the messenger who tells Paul Revere what to watch for in the tower of the Old North Church, muses on Otis's words. " 'That a man can stand up'—as simple as that. And the strange new sun rising in the west. A sun that was to illumine a world to come."

Purplish and sentimental, yes, but to a young man growing up surrounded by the legend of the Revolution, it was stirring, and the sun Forbes wrote of in her fervid way illumined Bloomberg's childhood. Holding a copy of the book at the beginning of an interview with NEWSWEEK at New York's Gracie Mansion last week—he had written of its influence on him in his 1997 memoir, so I brought one with me—Bloomberg said with a flourish, " 'One if by land, two if by sea!' " He smiled, still gazing at the cover, before snapping back to the autumn of 2007. "I don't know why I loved this book so much."

The question is actually not a very difficult one. He loved Johnny Tremain because Johnny Tremain was a hero, a boy of obscure origins who made himself indispensable to Revere and others through hard work and ingenuity. It was a very American story, one in which dedication was rewarded to the sound of trumpets. The drama of Bloomberg's young life, which has become the drama of his entire life, took shape as he absorbed stories of Revolutionary heroes, both real and fictional, who acted alone and boldly for the good of the many—and who were therefore celebrated and commemorated as great men, the kind of men whose graves Bloomberg and his Scout troop festooned with flags. Bloomberg decided early on that he wanted to be a great man, too. Most teenagers, if they can, seek glory in sports. Bloomberg was not a great baseball or football player, and so he had to look elsewhere to find his place in the world.

He had to search no farther than the end of his street. There, every April, at the corner of Winthrop and Playstead, came the re-enactment of Revere's ride. The townsmen who formed the parade would stop at Gaffney's funeral home, Bloomberg recalls, for "a tot" before proceeding to Medford Square, where a Scout would recite Longfellow's "Paul Revere's Ride" on what Bloomberg recalled was a "big stage." Let Bloomberg tell the story of his own year in the sun: "Perhaps the proudest moment of my early life was being chosen one year to read [Longfellow's poem] on the raised platform overlooking the assembled revelers," he recalled in his memoir. "With 'Paul' on his prancing horse in front of me, the high school band playing John Philip Sousa marches, and newspaper photographers snapping away, I read aloud into a real live microphone the famous poem: 'Listen, my children, and you shall hear / Of the midnight ride of Paul Revere, / On the eighteenth of April, in Seventy-five; / Hardly a man is now alive / Who remembers that famous day and year … / One, if by land, and two, if by sea; / and I on the opposite shore will be … / And yet, through the gloom and the light, / the fate of a nation was riding that night …' I can remember it still."

Note what else he remembers, too: The raised platform. The assembled revelers. Photographers snapping away. A real live microphone. For Bloomberg, public service and public attention are inextricably linked, and he thrives in the spotlight. From TR to FDR to Reagan, our greatest politicians have understood that showmanship is a critical element of leadership, and Bloomberg is among the best showmen and leaders at work in American politics.

While he has been on a lot of big stages since that Patriots' Day in Medford Square, it was perhaps inevitable that he is now thinking about taking a turn on the biggest stage of all: a campaign for the White House. The subject of a Bloomberg presidential bid is on a lot of people's minds, including the incumbent's. Landing at the Wall Street heliport earlier this year, after the mayor announced he was leaving the Republican Party to become an independent, President Bush gestured to Marine One and told Bloomberg: "That bird could be yours."