Two years ago, I had what I thought was a great idea for fixing our schools: Double all principals' salaries. My column about this did not win universal approval. I could not even persuade the principals I knew, who said it wouldn't work unless teachers got a big raise too.

But I remained true to the concept. I thought paying $150,000 a year, or more, would ensure we got the best people in the most important single job in any school, and lure many more capable people into education.

Now, finally, someone has seconded my motion. And this person has more than enough money and power to make it happen--at least in the 157 public schools his company runs.

My unexpected (and likely unaware) supporter is Chris Whittle, founder and chief executive of the Edison Schools, a for-profit company that runs schools in mostly low-income neighborhoods in 19 states and the District of Columbia.

Whittle has just published a book, "Crash Course: Imagining a Better Future for Public Education" (Riverhead, 288 pages), which you can get for $16.47 on Amazon.com. It is a wild read -- part confessional memoir, part annual report, part speculative fiction -- and well worth the money, particularly his wise affirmation of my thinking in Chapter six, "Next-Level Educators."

"Anyone who has been around schooling very long knows this: An underperforming principal guarantees an underperforming school, and a good one gives you a chance at a good school," Whittle writes. "Principals are one of the key leverage points within a school."

Then he notes the annual salaries of other key service providers: physician in internal medicine, $175,000 to $250,000; 747 captain, $240,000 to $275,000; hospital head, $135,000 to $200,000; large-store manager, $120,000 to $200,000. He compares those salaries to what we are paying on average to our 90,000 public school principals -- $75,000 to $85,000.

If the pay structure holds, Whittle writes, "only those prepared to make a dramatic economic sacrifice will be our schools' leaders. Thousands of those heroic individuals are out there -- they make up the best of our principal corps today -- but are there 90,000 of them? History and our record of school performance tell us no. So either we dramatically increase the pay of our school leaders or we accept the inevitable result."

I noted in my column that since there were relatively few principals in any district, a big bump in their pay would not be a budget buster. Whittle, who unlike me has actual experience running schools, makes this argument with much more confidence and sophistication:

"Let's assume there are 90,000 principals with an average pay of $80,000 each. That means we spend about $7.2 billion per year in principal compensation, or just 1.75 percent of total annual expenditure on K-12 education. The math is pretty simple: We could increase principal pay in the United States to $200,000 per year by adding to or reallocating just over 2.6 percent of annual K-12 spending. We could finance this investment by directing a portion of our annual education spending increases to it. Or we could find the money through allocation of our existing educational dollars."

He notes that Edison gives bonuses of $25,000 to $35,000 to principals who show an annual gain in student achievement of more than 10 percent and meet their budget targets. Before this incentive program began, the average Edison school gained about 4 percent a year in student achievement, he says. Since the bonuses program took shape, that gain has nearly doubled to 8 percent. (I can hear Whittle's many critics -- he is a favorite villain of the nation's teachers unions -- chortling at this, and suggesting the numbers are cooked to make his company look good. But let's assume for the moment that what he says is true.)

He proposes a new base salary for all principals of about $120,000 a year, with a bonus potential of up to $80,000. He says this will increase the candidate pool of principals, making it easier to find good ones, and sharply reduce principal turnover, which would also help schools.

The many good principals I asked about this almost all said that their most important job was hiring and inspiring good teachers, and they would be unable to do that well if faculty salaries did not also increase. They said these fat new principals' contracts should also make it clear that if they do not show significant increases in student achievement, they will lose their well-paid jobs.

Whittle makes the same argument, although that is the point where his book begins to wander into fantasyland, which I will explain in a moment.

"Crash Course" has many intriguing parts. The book reveals the moment when his board, worried about a beating Whittle was getting in the press, told him they did not want him in charge any more. He says he stepped back as ordered, but kept his seat on the board and still came to work every day, asking how he could help. After two years, the outlook had improved, and the board restored his power.

Whittle is a fine writer, and describes the state of American public education clearly and more or less accurately. His story of the Edison Schools' painful growth is a useful cautionary tale about the difficulties of being a pro-profit enterprise dealing with educators who do not have much faith in the free market. Some critics will contradict his numbers, but that has always been the case with Whittle. The fact that he is still in business 13 years after he launched the enterprise suggests that he has a firm enough grasp on reality. There is no denying that many of his schools, such at the four in the District, are helping low-income students.

But toward the end of his book, Whittle starts dreaming. He is very good at this. The idea for Edison Schools was a visionary concept. Anyone who has put in as many hours as he has struggling with the financial and managerial details of running a school system is entitled to speculate on how much better our schools could be if we did things very differently.

Still, I would have liked to have read more about how he made the Edison Schools work from 1992 to 2005 and less about how really wonderful our schools can be if we do three or four seemingly impossible things by the year 2030.

Among his more optimistic ideas is the notion that we can raise the national average teacher's salary from $46,000 to $70,000 by reducing the number of teachers by about a third. Hearing the growls of his labor critics, he congratulates the unions on their efforts to raise salaries and says reducing the number of teachers would not cut union revenue because the larger salaries would mean more money from each teacher.

How does Whittle expect to have fewer teachers, and not have to stuff 40 kids in each of their classrooms? He wants students to spend more class time working on their own, or with computers. He also wants to enlist students to perform some of the staff chores that cut into teacher time and school budgets. They could learn by doing, he says.

When I told Whittle I thought this was loony, he strongly objected, saying he had a plan to do it and had spelled it out in the book right down to the school budget level. That is true, but I learned long ago not to trust plans for schools that have not been tried out with actual students, parents and teachers. What I like about his idea for raising principal pay is that he has actually done it, and seen some positive results.

Whittle is no fool. He says he is not sure all of his ideas will work, and he knows how some of them will look to many people, particularly his tormentors in the media. He says one reporter heard him speculating on the benefits of students helping out at school and had a story in the paper the next day saying Edison planned to skirt the child labor laws.

Whittle has had great success following his dreams, and he seems to enjoy the inevitably bitter debates that some of his ideas inspire. That's fine. I just hope he focuses his energies on the most practical of his ideas, like giving the best school leaders a lot more money, and finding more politically acceptable ways to increase teacher pay too.