At first glance, he doesn't look like a street fighter. John Sperling, an 82-year-old former history professor, is an elf-sized fellow with gold-rimmed aviator glasses and a halo of gray hair. Twice divorced, he lives alone in an Italian-style estate near the sere hills of north Phoenix, where he is surrounded by citrus and pecan trees and paintings by Andy Warhol. As we meet in his poolside office on a sun-splashed winter day, he is retiring, almost shy.

But make no mistake: John Sperling, the man who put the profit into for-profit higher education, hasn't amassed a billion-dollar fortune by letting himself get pushed around. The longer we talk, the more his hard-charging attitude emerges. He drives a Jaguar. He favors a black leather biker jacket and a Greek sailor cap. He is direct, profane. And he enjoys nothing more than sticking it to the powers that be -- whether it's smug academic princes in the ivory tower or zealous antidrug warriors in the Bush administration.

Sperling is chairman of the Apollo Group Inc., a Nasdaq-traded holding company with a market cap of $7.5 billion, and founder of the University of Phoenix, the least by-the-book university imaginable. The Apollo Group owns the university, which makes it a school that you can attend and invest in at the same time. Comprised entirely of working adults (the minimum age is 23), the University of Phoenix is the largest private university system in the United States, with more than 140,000 students attending classes at 41 campuses. Factor in its distance-learning operation, and the University of Phoenix's reach extends across the world.

Sperling's Apollo Group is a rare success story in this down economy. Since going public in 1994, Apollo has racked up an annual growth rate of roughly 25%. Last year, it had $1 billion in revenue -- a 31% increase over 2001. Its distance-learning division claims nearly 60,000 students and an enrollment that's increasing at a rate of about 60% a year. Its stock has split twice and nearly tripled in price since its IPO in 2000, making it one of the few Internet companies to have prospered.

For those reasons and more, Sperling is beloved on Wall Street. For those reasons and more, he is loathed in many academic quarters. His critics accuse him of commodifying education, turning a social good into a market product. They dismiss the University of Phoenix as a "McUniversity" that delivers mass-produced fare at bland locations.

"John Sperling's vision of education is entirely mercenary. It is merely one more opportunity to turn a buck," says Scott Rice, a San Jose State University English professor who is writing a book on the effort to monetize higher education. "When education becomes one more product, we obey the unspoken rule of business: to give consumers as little as they will accept in exchange for as much as they will pay. Sperling is a terrible influence on American education." Sperling is used to such biting commentary. In fact, he seems to welcome it. "Why do people say such things about us?" he asks. "Fear! Fear! Fear! They're scared to death of us."

Even Sperling's harshest critics must concede that he is a visionary. He foresaw a growing demand for adult learning -- which now accounts for more than half of all college students -- and built a fortune by getting there first. Then, years before Marc Andreessen unveiled the Mosaic browser and supercharged the Web, Sperling saw that he could reach tens of thousands of additional students by putting the University of Phoenix's curriculum online.