Like his Lightning Thief star Percy Jackson, Rick Riordan is a demigod—at least in the eyes of his readers. With the release next May of the first title in his new middle-grade fantasy series, about ancient Egypt, he is set to become a pharaoh, too.

In The Kane Chronicles, Book One: The Red Pyramid, kids will meet Carter Kane, 14, and his sister, Sadie, 12, descendants of Egyptian magicians who battle gods accidentally released in the present. (Watch out for the god of chaos.)

“In my classroom, there was only one thing that was more popular than ancient Greece, and that was ancient Egypt,” said Riordan, who taught middle-school social studies and English for 15 years. “This was a matter of listening to a lot of fans, and a lot of young readers.”

For Disney-Hyperion Books, which has sold seven million copies of the Percy Jackson & the Olympians titles since 2005, The Kane Chronicles is an important way to attract kids, regularly, to the bookstore. After all, as each new Percy Jackson title came out each year, sales of the series—which the prolific Riordan always intended to be a five-book arc—snowballed. “When you have a series come out regularly, you build that anticipation,” said Jonathan Yaged, U.S. publisher of the Disney Book Group. “There’s nothing like that book a year. The marketplace is getting tougher, so when there’s something that resonates, kids and retailers gravitate toward it.” With series, unlike with one-offs, he said, “you build that momentum.”

In The Kane Chronicles, kids can expect a good dose of hocus-pocus. “In my research, I came across some fascinating things most people don’t know about Egyptian magic and how it came to be,” said Riordan. “Some of the earliest roots of magic go back to Egypt. Egyptian magicians were famed throughout the ancient world as absolutely the best.”

Riordan unveiled his new series at last weekend's Texas Book Festival.

This time Riordan chose to use a boy and a girl as the main characters. Even with a male main character in the Percy Jackson series, he found that both genders read his tales. “The Percy Jackson books were always plugged as good books for boys,” he said. “[But] you go to one of my events, it’s 50-50.” From chapter to chapter, Carter and Sadie will tag team as narrators. Rather than retell the same events, they will each advance the adventure. Like Percy Jackson, they will be “wise-cracking, first-person narrators,” said Riordan.

Unlike the children in The Lightning Thief, the Kane kids will not be half-god. “There aren’t demi-gods in Egyptian mythology,” said Riordan. “[But] the Kane family has a long history that goes back all the way to the time of the pharaohs.”

Expect Carter and Sadie to age about a year per book, said Riordan. So in 2011, they will be 15 and 13, and in 2012, they will be 16 and 14. Currently Riordan has three books planned in the series—subject to change. “I may end up going farther than that,” he said.

In The Kane Chronicles, Carter and Sadie will also be more “globe-trotting” than Percy Jackson. “They will be visiting quite a few other countries, as well as the United States,” said Riordan. He won’t reveal exactly how they will be able to do it. “That’s always the challenge with young adult books. Where are the parents?” he said. “You have to come up with some mechanism that will make it believable that these kids will be able to gallivant around the world.” In The Kane Chronicles, “The mom and dad are very much part of the story line... because of the family’s history and special connection to ancient Egypt.” The father, Dr. Julius Kane, is a PhD Egyptologist. “That’s his cover anyway. That’s what he tells people,” said Riordan.

As a teacher, Riordan said, he learned to use humor and relate to young people. And as a father who liked to read aloud to his sons, Haley, now 15, and Patrick, now 11, he also figured out what made kids laugh. With the new series, as with Percy Jackson, “They were my first audience,” he said. Riordan did experience a “bittersweet moment,” he said. With The Kane Chronicles, Haley, who was also the first to hear The Lightning Thief, at age nine, said, “Why does this story sound younger to me?” Of course, Riordan said, his son felt that way because he is now six years older.

Reading aloud to his sons helps him figure out which wisecracks need tweaking. “They don’t really have to comment. I can tell by their expression,” said Riordan. “If I write a joke that I think is hilarious, and they don’t laugh, I know I have to fix it. I get the reaction from them, and it’s just the best laboratory I can think of for writing kids’ books.” (His wife’s role in their San Antonio home: “de facto office manager,” he said.)

As a former teacher, Riordan likes to hear from librarians about how their mythology sections are “getting a workout now,” he said. “If The Kane Chronicles can be a gateway into Egypt in the same way, I will feel like I’ve done something good.” To write The Kane Chronicles, he researched the ancient Egyptian myths.

What’s next for Riordan? He’s currently working on the Camp Half Blood spin-off from his Percy Jackson series, which debuts in fall 2010. “The world of Percy is going to continue,” Yaged said.

Riordan isn’t quite sure what else he'll tackle. “I love Norse mythology, I love Chinese mythology, Indian mythology. The world is wide open,” he said. “I could certainly make a career just doing different treatments of mythology, and I would be happy as a clam.” But, he added, “I have other ideas that are not mythology-based.”

The manuscript for the new book has not been circulated to film companies yet. “[It’s] under very tight control with just me, my editor and my agent,” he said. But he likes movie adaptations, if they work well. Percy Jackson & The Olympians: The Lightning Thief from Fox, directed by Chris Columbus, will hit theaters on February 12, 2020. Its cast includes Pierce Brosnan, Rosario Dawson, Catherine Keener, and Uma Thurman.

Disney is not revealing the size of its first printing for The Kane Chronicles yet. “That’s going to be our next announcement,” said Yaged. “It’s changing every day.” Brilliance Audio will simultaneously release an audio version of the book.

Kids and booksellers are already marking their calendars for May 4, the release date of book one in the new series. Josh Stricker, 14, the proud owner of signed copies of all five Percy Jackson books, plans to order early and pick up the new book on May 4 at BookPeople in Austin, Tex. “It’s been a little over a year since he’s published a book, and I’ve read the last one enough times,” he said. “I want to read something new by him.”

“The vast majority of our kids prefer series,” said Topher Bradfield, children’s outreach coordinator at BookPeople. “They want something that has a character that continues to grow. They get very comfortable with the idea of following a character through a set of books.” Indeed, BookPeople attracts 1—4,000 people any time Riordan visits the store, and it runs a six-week day camp called Camp Half Blood, based on the Percy Jackson series. Last summer more than 500 kids attended the camp.

Riordan’s special ingredient, according to Bradfield, is his sense of humor. “Fantasy is popular, but the thing that’s really, really popular is something that’s funny,” he said. “Rick has kept his books intelligent and sharp and funny and adventurous at the same time. That’s a winning combination.”

Riordan’s books hook reluctant readers, Bradfield said. “The boys who are really on the fence about whether this book is going to be as fun as playing a videogame—Rick’s books have been vital in terms of tapping into that group of kids.”

Bradfield and others at the Texas Book Fair last weekend heard Riordan read part of the first chapter of The Red Pyramid. “He has a really wonderful way of roping you in,” said Bradfield. To wit, Riordan ended with the Kane kids’ dad blowing up a museum of antiquity. To learn what happens next, Bradfield, like countless other fans, needs to wait for May 4.