“If you want to understand where ideas come from, they come from cities, which are social and economic engines,” he says. “When you put people in close proximity to one another, we leverage each others’ skills and talents. This is the motor force of our economy. “

Moreover, unfettered suburban expansion, which he has called “the great growth illusion,” has been proven by the economic crash to be unsustainable and unappealing to the young, he says.

“What’s been happening here in America, this suburban thing … that’s over. There is a generational shift.”

Some critics

That’s the sort of pronouncement that makes Florida’s critics, of which there are a fair share, gnash their teeth. Some dismiss his theory as elitist, and critics on the right and the left say it lacks academic rigor, overstates the role of urban creatives, glosses over the downside of gentrification and ignores the abiding allure of the suburbs, where the majority of Americans — including multitudes of creative types — are perfectly content to live.

“He had one idea and he’s going to stick to it,” said Joel Kotkin, a California writer and urban historian who has often debated Florida. “He’s giving a well-heeled sector of our society what they want to hear — that being hip and cool is great, and that people want to live in high density. It doesn’t have anything to do with people having children and buying a house that’s affordable.

“It’s a very good theory for a small segment of society, and not an unimportant segment. But it’s very limited. There’s not enough yuppies on the planet to save Detroit,” Kotkin says.

More fans

But to his legions of acolytes, Florida has been the prophet and standard-bearer of an undeniable urban turnaround evident in Google’s moves into downtown Chicago and Ann Arbor, Mich., and the conversion of San Francisco’s skid row and forgotten Brooklyn neighborhoods into hotbeds of startup tech, among many examples. His broadest influence, along with a measure of celebrity (Bono name-dropped him at an Irish economic conference last year), grew out of the embrace of his theory by urban activists, business groups and mayors from Miami’s Manny Diaz to New York City’s Michael Bloomberg.

“He named something that everybody was fumbling around in the dark with, and he turned on the light,” said Christopher Leinberger, a Florida friend and collaborator. “In the urban world he is one of the stars. He’s a household name. And a real lightning rod.”

The original edition of The Rise of the Creative Class sold more than 300,000 copies, a startling number for an urban-theory book that, while readable and sprinkled with anecdotes, is full of charts and statistics. It spawned a lucrative second career for Florida as a public speaker and a consultant to cities and companies looking to burnish their creative cred.

It didn’t hurt that Florida, 54, has what used to be called matinee-idol looks. Tall, dark, fit and fashionably clad, he seems the embodiment of the creative type.

Or maybe it did hurt. In Toronto, where he arrived to great fanfare after the university created the institute just for him, activists started an anti-Florida website that took aim no just at the inequality they said he promotes, but also at the Floridas’ sumptuously renovated home.