With two new trilogies, Percy Jackson author Rick Riordan stands likely to boost his already (ahem) Olympian output—and sales. Disney-Hyperion will release one million copies of The Red Pyramid, first in his Kane Chronicles series inspired by ancient Egyptian magic. An as-yet-unnamed Percy Jackson spin-off will follow, which will combine familiar characters with some new half-human, half-Greek-god kids.

Until now, Riordan has stuck to one book a year. "I've set myself a challenge of putting out two books a year so the readers don't have to wait longer than a year for either series," said Riordan. "That's a pretty big jump for me." The extra work will pay off if readers take to the new series the way they did to Percy Jackson. There are 12 million copies of that five-book series in print, and sales more than doubled after the opening of 20th Century Fox's Percy Jackson and the Olympians: The Lightning Thief, which has grossed $180 million worldwide to date.

Global book sales have been strong too. So far 34 countries are publishing Percy books. And the U.K., France, Germany, Finland, Israel, and Brazil are already signed up for the Kane Chronicles. "I have no doubt the new series will be licensed by 34, if not more," said Ellen Greenberg, who handles foreign rights at the Nancy Gallt Literary Agency. It's all proof of "just how universal a good story is," Greenberg said. "It's not an American story."

So with a film under his belt, is Riordan, 45, going Hollywood? Hardly. Instead, the former middle-school teacher is holing up in his family's San Antonio house working on the second Kane Chronicles book in what he describes as a "spare, unexciting" guest room. "I'm like Percy. I'm sort of ADHD," said Riordan. "I don't need a lot of distractions around me."

In fact, he didn't even take a break to catch the Fox film, though he did stop by the set. "I made the decision that I'm not going to see it," he said. "My own vision of the characters and the setting and the story—I have a very clear idea of the way things are. I don't want that vision changed by the movie version." (He regrets seeing the first few Harry Potter movies because he could not get Daniel Radcliffe's image out of his head when he read book seven.)

But he's not looking a gift film in the mouth. "I'm grateful to the movie because it brought so many people to the books," Riordan said. And he said his wife and kids enjoyed the flick—"as long as they didn't try to compare it with the books." Other Percy fans felt similarly. Nick Capriola, 14, who helps his mother, Little Shop of Stories owner Diane Capriola, run the store's Camp Half-Blood camp, said the film was "like the book rearranged."

Fox, which bought the movie rights to the Percy characters in 2004, has not yet announced plans for a sequel to The Lightning Thief, the DVD of which is set to release this June. "Fox has what we in the publishing world would call ‘first dibs' on The Sea of Monsters," said Riordan's agent, Nancy Gallt. "They have not, as far as we know, contacted us to exercise those first dibs." The Gotham Group, which is handling film rights to the Kane Chronicles, can't say who might be interested in the new series, said Eddie Gamarra, literary manager/producer for the company.

Despite passing on the movie, Riordan squeezes in time to tweet to his more than 7,000 "camphalfblood" followers on Twitter, to write in his blog, and to work with Disney-Hyperion on upcoming Kane Chronicles puzzles and online giveaways. (The Kane Chronicles site already contains the first chapter of The Red Pyramid.) And from May 4-15, Riordan will break for a book tour that will start at Symphony Space in New York City and end at Barnes & Noble in San Antonio.

Earlier this month, Riordan visited the Metropolitan Museum of Art—a location featured in both the Percy Jackson and Kane Chronicles series. On March 14, he talked to a sellout crowd of 700—about half kids, half adults—in the Met's auditorium. "He spoke about what it was like to get to know these gods and heroes as he was growing up," said Met spokesman Elyse Topalian. He also showed covers of his books from around the world and read an excerpt from the Kane Chronicles.

The Kane Chronicles stars Carter Kane, 14, and his sister, Sadie, 12—descendants of Egyptian magicians who battle gods accidentally released in the present. From chapter to chapter, the siblings tag team as first-person narrators. "I didn't know how that would be, telling a novel from a first-person point of view from a 12-year-old British girl," said Riordan. "She's just endeared herself to me." She isn't based on anyone he knows, though, he said, "I certainly have strong-minded women in my life—my mom, my wife, my editors!"

For the Percy spin-off series and the later Kane Chronicles books, Riordan will be working with a new editor, Stephanie Lurie, editorial director at Disney-Hyperion. Earlier this month Jennifer Besser, who edited all five Percy books and The Red Pyramid, moved to Penguin to become v-p and publisher of G.P. Putnam Books for Young Readers.

In the first Percy spin-off, Riordan alternates between three different characters, which "adds a lot of suspense," said Lurie. "He brings the same humor and the same love of mythology to all the projects." But Lurie and Riordan won't reveal many details. "Percy has a part to play in the new series," said Riordan. "What that part is I can't say without giving away a pretty huge part of the plot." Percy and the other characters will continue to grow older, but Riordan will include younger kids, too. "I don't want them all to be 17 or 18," said Riordan. "I'm still targeting my core audience, which is, say, 9 to 15. That's the sweet spot."

As in years past, several bookstores will host Percy-themed summer camps for kids ages nine to 13. BookPeople in Austin, Tex., hosts five one-week, 8-to-5 camps (for 75 kids per session) that run from July 12 through the last week of August. Camps sold out in an hour and a half last November, and 500 kids are on the waiting list.

In Decatur, Ga., Little Shop of Stories' Camp Half-Blood is based out of the bookstore. Kids visit a nearby church parking lot when it's time for "chariot" races (in pedi-cabs), get to hear original myths, create hieroglyphics, and can expect Greek and Egyptian feasts and trips to the Egyptian and Greek galleries at Emory University's Michael C. Carlos Museum of Antiquities.

Brownstone Books in Brooklyn will offer four weeklong Percy day camps—complete with archery, "sword" fighting, and camp assignments. And at the YMCA's overnight Camp Kern in Lebanon, Ohio, 300 or so nine- to 16-year-old campers will participate in a Percy Jackson theme day, with counselors dressed as characters as well as an adventure game leading them to Medusa's lair, among other places.

What's next for Riordan? For now, he is thinking only of his two new trilogies, not about what will follow them. In March, he turned in the first Percy spin-off book-after test-reading it with his initial editors: sons Haley, 15, and Patrick, 12. "They said it was actually their favorite one so far, even more so than Percy," Riordan said. "It usually takes us about three or four nights to get through the whole thing," he said. "If they keep saying, ‘don't stop, don't stop, read another chapter,' I know it's working."