These days, it requires a Herculean effort to keep up with Rick Riordan. The god of mythology-minded tween literature has his hands full, finishing the third installment in his five-book Heroes of Olympus series, touring for the concluding book in the Kane Chronicles, traveling to Europe to do research for an all-new series based on Norse lore – and he shows no signs of letting up.

Here we offer readers an exclusive peek at the cover of the third Heroes book, The Mark of Athena, due out on October 2. Disney-Hyperion is revealing the book’s first chapter today, May 31, at the Heroes of Olympus Web site. Then on June 5, timed with the opening of BookExpo America, the publisher will launch a new Web site,, with the tagline: “Whose camp are you in?” “We anticipate a lot of kids wearing purple or orange T-shirts to signify [their affiliation],” says Suzanne Murphy, v-p and publisher of books at Disney Publishing Worldwide, and the mother of a 12-year-old boy who was a reluctant reader until he discovered The Lightning Thief.

Enthusiasts can also look forward to Fox 2000’s release next March 15 of the movie Percy Jackson & the Olympians: The Sea of Monsters, with Logan Lerman returning in the lead role and Thor Freudenthal replacing Christopher Columbus as director. (Percy Jackson & the Olympians: The Lightning Thief, based on the first book in the series, was released in February 2010.) Though such films inevitably disappoint some fans, they also draw new readers to the novels, says Nancy Gallt, Riordan’s agent since The Lightning Thief: “They’re like 90-minute advertisements for the books.” Murphy confirms this influence, adding, “There were tremendous backlist sales when the first movie came out.”

Disney has not yet finalized details for Riordan’s fall book tour for Athena. But the author is hardly sitting still: for his tour earlier this month for The Serpent’s Shadow, the conclusion of the Egyptian mythology-based Kane Chronicles, he pre-signed as many as 1,000 books at each stop. After October’s Athena comes the fourth entry in the Heroes of Olympus series, due out in fall 2013.

Despite his hectic schedule, Riordan remains very hands-on with every aspect of his books. To come up with The Mark of Athena cover image, he collaborated with John Rocco, who won a 2012 Caldecott Honor for Blackout and who has designed all of his covers, beginning with The Lightning Thief in 2005. “It has become a very collaborative effort,” says Riordan. “We do a lot of talking and a lot of thinking about what the cover images should be.” As the Athena jacket reveals, readers can expect a battle between the Greek gods’ offspring in Camp Half-Blood and the Roman gods’ offspring in Camp Jupiter.

The author’s family – his wife, Becky, and sons Haley, 17, and Patrick, 14 – also contribute to Riordan’s literary efforts. Haley, who inspired Riordan to write the original Percy Jackson series, recently finished writing a 30-page entry for his father’s Demigod Diaries anthology. Patrick is a careful, avid reader who asked his Dad to pay him $10 for every mistake he caught before his last two books went to press. He wound up earning $400 for one and $300 for the other – a nice addition to his college savings fund. Becky, a visual artist, continues to be his first editor.

They accompany the author on research trips, too. In 2009, the Riordans traveled to the Mediterranean as part of a sweepstakes prize; the winner’s family got to meet the author in Athens. The excursion, Riordan says, “reinforced to me that as much as I know about Greek mythology, there’s always more. Talking to the Greek tour guide and climbing the steps of the Acropolis, I was hearing stories I’d never heard before.” An Alaska voyage inspired The Son of Neptune, the second Heroes of Olympus book, and a cruise to the Baltic and Scandinavian countries last summer provided fodder for Riordan’s upcoming Norse series. “It was fascinating to see the armor and the weapons from the Viking times and the cauldrons made out of gold,” he says. Though wherever he travels, Percy Jackson seems to follow. “When we went into the Stockholmmuseum,” Riodan says, “I expected to see lots of things on Norse mythology, and we went into an exhibit of Greek mythology! In Sweden!”

When he isn’t on the road, Riordan continues to write in the quiet, pecan tree-shaded guest room of his one-story San Antonio home. “Like Percy, I’m very ADHD,” he says. “I like to have a simple workplace.” A couple of John Rocco covers hang on the wall and, he says, “That’s about it. People ask if they can take a tour. I say, ‘You’re going to be disappointed!’ ”

Riordan says he works best when he doesn’t try to adhere to a consistent schedule. “Because I am kind of distracted, I don’t tend to sit at my desk 9 to 5,” he says. “It can be two hours a day, or, when I’m in the final editing stages, it can be 14 hours a day.” A week ago last Sunday, he got up at 5 a.m. and worked until 5 p.m., emailing his editor with his final changes on The Mark of Athena the next morning.

Of course, “final” is an interesting word to use about a writer who is still finishing Heroes of Olympus, just beginning his Norse series, and writing a short Percy Jackson story for Guys Read, the web-based literacy program. He has more than a dozen ideas in a folder called “Other Novel Ideas” on his MacBook Air. “Some I’ll get to, some I won’t,” he says. “It’s a wonderful problem to have. I have more ideas than I’ll ever be able to write in a lifetime.”

For now, Riordan, who has also published adult books in his award-winning Tres Navarre detective series, plans to stick with stories for middle-readers. “The age group that I know the best is middle grade because I taught for so long –for 15 years – and I know those kids,” he says. “I don’t think I would ever inch my way up to YA. That audience is very well served. There are a lot of wonderful writers writing for YA. I feel like I’m in the right place.”

It’s clear that Riordan loves his characters, his subject matter, and his job. “If you’d asked me seven years ago what I’d be doing today, if I heard I’d be a bestselling children’s author, I would have laughed,” he says. “I just did not see that coming. I certainly hope that I’ll be able to continue what I’m doing now because I love it so much. I feel incredibly fortunate to have had the level of success I’ve had. I was just writing stories for my own sons.” But it reminds him of his old job. “I still kind of feel like I’m a teacher,” he says. “I just have several million students in my classroom.”