If you're not a teenage boy or a children's bookseller, you may have never heard of Alex Rider, the 14-year-old super spy who stars in a series of novels by Anthony Horowitz. But Alex Rider may be poised for bigger things when Operation Stormbreaker, a movie based on the first Alex Rider book, opens in the U.S. on October 6.

Philomel Books, Alex Rider's American publisher, is hoping for the kind of sales boost the books saw in the U.K. when the movie was released there in July: Alex knocked Harry Potter off the top spot on children's bestseller lists, and landed seven titles—the six original novels plus a movie tie-in—in the top 10.

While the series has been a bestseller in England since the first book debuted in 2000, it's been slower to catch on in the U.S., said Michael Green, v-p and publisher of Philomel. "Alex seemed to explode in the U.K., and Anthony Horowitz became a household name. Unfortunately there are a lot more households in the U.S., so it takes a lot more here," Green said. He added that the series has been gaining readers with each successive title since May 2001, when Stormbreaker appeared in the U.S. "We have had a ladder of success with these titles, with each book in the series getting a higher first printing and bigger sales," he said. "Then with the fourth title, Eagle Strike, we got a New York

Times bestseller." Nielsen BookScan numbers indicate sales for the hardcover of Stormbreaker are at 6,000 copies, with the most recent addition to the series, Ark Angel(April 2006), selling 57,000.

Nine million Alex Rider books have been sold worldwide, with four million of them in the U.S., according to Philomel.

But with the premiere of Operation Stormbreaker next week, the best may be yet to come.