As booksellers await the seventh and final Harry Potter title, due in July,another promising fantasy series has quietly gained traction among young readers and booksellers. It has even attracted Hollywood and an award-winning Potter film director. The third installment of Rick Riordan's Percy Jackson and the Olympians series, titled The Titan's Curse, is due from Hyperion next month, with a 150,000-copy first printing.

Riordan's first book in the series, 2005's The Lightning Thief, has sold 275,000 hardcover and paperback copies combined; his second, The Sea of Monsters, which sold more than 100,000 copies in hardcover, has just been released in paperback. Last week Variety announced that Chris Columbus—who has directed two Harry Potter films—has signed on to direct and produce The Lightning Thief.

Percy Jackson is a wisecracking dyslexic boy with ADHD who also happens to be the son of Poseidon; in a modern-day setting, he finds himself caught up in stories from Greek mythology. Booksellers are keen on Riordan's approach, complimenting not only his use of classic story lines but the contemporizing twist of having the hero be learning impaired.

At Wellesley Booksmith in Wellesley, Mass., children's buyer Alison Morris reports The Lightning Thief sold 128 copies in hardcover and 525 in paperback, and was the bestselling title at her store last year. “And Sea of Monsters was our third bestselling title, behind Lemony Snicket.” Smith has ordered 400 copies of the new book for a launch party.

She says that the books are especially appealing to reluctant readers, particularly boys. “The action takes off on the first page,” she said. “Riordan takes the old familiar stories, which have gore, action and romance, and makes them work in a contemporary setting.” Morris added that the books' sympathetic portrayal of Percy's dyslexia and ADHD helps some readers identify with the characters more easily.

BookPeople in Austin, Tex., got behind the books very early, and has moved more than 500 copies of The Lightning Thief in hardcover and some 1,200 paperbacks. Last year the store promoted the hardcover of TheSea of Monsters, and has sold more than 800 copies thus far. They've ordered 500 copies of The Titan's Curse for their own May 1 party.

Riordan's sales at BookPeople can largely be attributed to Topher Bradfield, the store's children's outreach coordinator, who in 2006 was inspired to create “Camp Half-Blood,” a summer camp based on Riordan's series.

BookPeople plans three more Camp Half-Blood sessions this summer, each with different mythological underpinnings, including Labors of Heracles, the Lyre of Orpheus, and Theseus and the Minotaur. “We've got 80% of the kids from last year coming back,” said Bradfield. Hyperion Books for Children is providing $6,000 to help cover the cost of the camps and pay for one student from a disadvantaged school district to attend each of the camps for free.

Bradfield's Camp Half-Blood idea caught the attention of Diane Capriola, owner of Little Shop of Stories in Decatur, Ga. She has been working with Bradfield to devise her own Camp Half-Blood to take place this summer. “Parents like the idea of a literary camp because it is educational,” Capriola says. “Kids like it because it doesn't seem educational.”

Scott Meyer, owner of Merritt Bookstore in Millbrook, N.Y., said he only recently discovered the series—after a sales rep sent him copies on tape. “I came late to the books,” said Meyer, “but once I heard them I immediately knew I wanted to handsell them in the store. We're always looking for the next Harry Potter, and this is a very good series to promote in that vein.”

Nancy Gallt, Riordan's agent, says she always knew Riordan's books might bear comparison to those about the boy wizard. But she sees one distinct advantage her author has over J.K. Rowling: “Rick is writing them faster—one per year—which means his readers won't grow up faster than the characters in the book.”

With the total number of Percy Jackson books set at five, that means Riordan's fans will be able to read their final installment in spring 2009. After that? “We're already talking about prequels and spin-offs,” Gallt says. “Rick has tons of ideas.”