BY GLENN WHIPP>FILM WRITER

When you're making a movie based on a novel that has spent more than two years on The New York Times best-seller list and was read last year by more book clubs than any other title, you'd better not muck it up.

That's Marc Forster's view, anyway. Forster ("Finding Neverland," "Stranger Than Fiction") had directed the movie adaptation of Khaled Hosseini's "The Kite Runner," a book that isn't just read out of obligation. OK, maybe it is read out of obligation, but the act of reading usually produces passion and a tell-a-friend impulse that has kept the book flying out of stores.

"You can't disappoint those readers," Forster says. "That's why I fought to keep the movie as authentic as possible.

"It's in Farsi. There are no stars. I promise, it hasn't gone Hollywood."

Why has "The Kite Runner" so captivated readers? The decades-spanning story follows the guilt of Amir, a wealthy man who fled Afghanistan after the Soviet invasion, leaving behind his childhood friend, the son of his father's servants. Amir returns to Afghanistan 20 years later, just as the Taliban take over, to find his friend.

"The story touches a deep emotional chord," says Forster, currently preparing the next James Bond movie. "We've all done something in our lives that we've regretted, something we wish we could change.

"Then, too," Forster adds, "it hits our present consciousness. It's set in the Middle East, it's about something we've done wrong, something we wish we could do again."

Forster believes the movie "can't possibly be better than the book."

"The only thing you can do is make a companion piece that you hope captures the story's spirit," Forster says. "I think that's a worthwhile pursuit. At least it's worth a try."