Scholastic has signed Rick Riordan, author of the bestselling Percy Jackson series, for an ambitious multiplatform middle-grade adventure series that will debut next September. The 39 Clues will incorporate a book publishing program, collectible cards, an online game and more than $100,000 in prizes. The program features 10 books about a powerful and mysterious family called the Cahills; the series will be published over the course of two years starting with The Maze of Bones. The 39 Clues game begins on September 9, 2008; through the cards and the program’s Web site (, which has not yet gone live, readers will be able to gain clues and information not included in the books.

Riordan has outlined the story arc for the series and has written the first volume, but the subsequent books will be penned by Gordan Korman (Schooled), Peter Lerangis (the Drama Club series), Jude Watson (Premonitions) and other authors yet to be announced. Six collectible cards will be included with each book, each containing a unique code that allows children to register and manage their collections online; 350 cards will be created for the promotion, with packs of 16 cards available for separate purchase.

“With the breakthrough concept of The 39 Clues, Scholastic is uniquely positioned to reach millions of young people who are readers, gamers, collectors, or all three, and encourage them to participate in a multi-dimensional 21st-century reading experience,” said Ellie Berger, president of Scholastic Trade. The program will simultaneously launch in the U.S., U.K., Australia, New Zealand and Canada.

According to Riordan’s agent, Nancy Gallt of the Nancy Gallt Literary Agency, Scholastic was already familiar with Riordan’s work since it had previously acquired book club rights to the Percy Jackson series. “We were very flattered that they thought Rick would be the right person for this, and that they were willing to wait for him to be available to do it,” Gallt said. “We’re also very grateful to Hyperion [publisher of Riordan's Percy Jackson books] for letting us pursue something that was very dear to Rick’s heart. He really did it because he’s interested in gaming, in the online component. This was an opportunity to get to boys in a multimedia kind of way.”