William J. Bennett, the former secretary of education during the Reagan administration and best-selling author who once wrote, “So far, there is no good evidence that most uses of computers significantly improve learning,” has become chairman of new company that will open an online school this fall for students in grades K-12 nationwide.

As a past critic of educational technology, Bennett once gave schools’ efforts to increase the use of computers in teaching an F-minus. In his books The Book of Virtues and The Educated Child: A Parent’s Guide From Preschool Through Eighth Grade, he advocated traditional educational approaches and values.

Yet, Bennett is now joining the list of companies and school districts willing, even eager, to sail into uncharted cyberspace—despite skeptical child development experts and the spiraling business failure rate in the dot-com world.

“Education is what America cares about the most, and technology is what we do best,” said Bennett, who introduced his new online school Dec. 28. The for-profit school, called K12, begins enrollment next fall in kindergarten through second grade and promises eventually to offer lessons in all grades, from math and science to arts and sex education. Costs would range from $25 for skill tests to about $2,000 for full lesson plans and software for a year.

K12, based in McLean, Va., was launched with a $10 million investment from Knowledge Universe Learning Group, a division of Knowledge Universe that was founded in 1996 with investments from Oracle’s Larry Ellison and financier Michael Milken.

The company has recruited David H. Gelernter, Yale University computer science professor and recipient of a package from the Unabomber that exploded in 1993, as its chief technology adviser. Gelernter has expressed similar skepticism of internet education ventures and the use of educational technology.

Although many internet companies offer online curriculum and schooling without much proof that it improves learning, Bennett has made the decision to try to get it right, said Jason Bertsch, vice president of government relations and public affairs at K12.

“He thinks technology can improve student achievement—but, so far, it hasn’t,” Bertsch said. “Most studies show that it hasn’t had a significant impact on achievement—and that’s why we are doing this.”

Though several states—including Florida and Kentucky—have opened online high schools, Bennett’s venture is among the first to envision shepherding a child from kindergarten to a high school diploma.

Backers of educational technology say the internet can help children isolated from traditional schools by distance or disabilities, and it can benefit children already schooled at home by their parents.

“I can see the benefits of an online learning program for children being home-schooled. I can see such a program providing an enormous enhancement to a teacher in a remote community,” said Lauren E. Pomerantz, program coordinator of the California Space and Science Center.

However, Pomerantz added, “I think that most children do not have the discipline to start such a program in kindergarten or elementary school, and most parents do not know how to implement such a thing.”

Sandra Feldman, president of the American Federation of Teachers, expressed similar misgivings: “An excellent elementary and secondary education cannot be based solely on technology. We will have to wait and see if the quality of this particular product is as grandiose as Mr. Bennett’s quotes.”

The going has been bumpy for some online schools. Teachers have to keep up student interest with interactive lessons, guard against student cheating, and do without body language or verbal cues to tell them whether students understand lectures.

And in October, a 15-year-old in an online charter school in California hacked into the system and racked up $18,000 in damage, knocking the school off-line for two days and destroying homework assignments, lesson plans, and attendance records. But the marriage of education and technology is needed, say educators who believe teaching is becoming more difficult in today’s environment. Growing enrollments and shrinking budgets are leaving less room for one-on-one, hands-on learning at the side of an attentive teacher.

“We shouldn’t be stuck with one model,” Bennett said.