Since 1985, that's been the gist of Pizza Hut's Book It, an incentive program used by 50,000 schools nationwide to reward young readers with free pizzas. The program is now under attack by child-development experts who say it promotes bad eating habits and turns teachers into corporate promoters.

Book It, which reaches about 22 million children a year, "epitomizes everything that's wrong with corporate-sponsored programs in school," said Susan Linn, a Harvard psychologist and co-founder of the Campaign for a Commercial-Free Childhood.

"In the name of education, it promotes junk food consumption to a captive audience ... and undermines parents by positioning family visits to Pizza Hut as an integral component of raising literate children," Linn said.

Linn's organization, hoping to capitalize on a surge of concern about child obesity and junk food, this week called on parents and educators to end their schools' participation in the long-standing program. Linn noted that many schools are trying to reduce students' access to soda, and said Book It should face similar scrutiny.

But the program - which has given away more than 200 million pizzas - has deep roots and many admirers at the highest levels of politics and education. It won a citation in 1988 from President Reagan, and its advisory board includes representatives of prominent education groups, including teachers unions and the American Library Association.

"We're really proud of the program," said Leslie Tubbs, its director for the past five years. "We get hundreds of e-mails from alumni who praise it and say it helped them get started with reading."

Dallas-based Pizza Hut says Book It is the nation's largest reading motivation program - conducted annually in about 925,000 elementary school classrooms from Oct. 1 through March 31. A two-month program is offered for preschoolers.

Participating teachers set a monthly reading goal for each student; those who meet the goal get a certificate they can redeem at Pizza Hut for a free Personal Pan Pizza. Families often accompany the winners, turning the event into a celebration that can boost business for the restaurant.

Teachers find the program an enjoyable way to build interest in reading, Tubbs said. "We're helping them to do their jobs," she said.

At Strafford Elementary School in Strafford, Mo., the roughly 500 students collectively read 30,000 books a year with Book It's help, said principal Lucille Cogdill.

"I don't have any negative things at all to say about it," Cogdill said. "I know there's concern about obesity, but Book It is not causing it, and the schools aren't causing it."

Chris Carney, principal at Bennett Elementary School in Fort Lauderdale, Fla., also is a Book It fan, saying it encourages family togetherness and provides a tool for persuading children to try books instead of video games.

"I don't want to see kids gorging pizzas," he said. "But the positive effects outweigh other effects."

Among those campaigning against Book It is Alfie Kohn, an author whose 11 books on education and parenting include "Punished By Rewards, which questions the value of incentive programs.

"The more kids see books as a way to get pizza or some other prize, the less interest they'll have in reading itself," Kohn, a former teacher, said in a telephone interview. "They tend to choose easier books to get through faster."

Another critic of Book It and the broader phenomenon of corporate incursions into schools is Alex Molnar, director of the Commercialism in Education Research Unit at Arizona State University.

He described Book It as a "dreadful program" that puts pressure on parents to celebrate with their reward-winning children at Pizza Huts.

"This is corporate America using the schools as a crow bar to get inside the front doors of students' homes," he said. "It's very hard for children whose parents who don't want to engage in this to not feel ostracized."

Molnar acknowledged that Book It is well-regarded by many educators and politicians, but said it might be reevaluated in light of rising concerns about child obesity.

"To the extent that this program is correctly identified as part of the problem, then there's a chance of reducing its scope," he said.