NEW YORK (AP) - Rick Riordan spent the past few months in hell, and liked it.
The million-selling children's author promises a "fair amount of drama" in "The House of Hades," Book Four of his "Heroes of Olympus" series set for release this week. Disney Hyperion has announced a first printing of 2.5 million copies and the 600-page novel already is in the top 5 on Amazon.com.
Book Three of the "Heroes" series, "The Mark of Athena," ended with Percy and Annabeth plunging into the Underworld and the Romans set to attack Camp Half-Blood. Riordan promises the adventures down under in the new book will be "very intense," even for a storyteller unbounded by human possibility.
"Some conflicts from the previous book will be resolved," he said during a recent telephone interview. "But I don't think Percy and Annabeth have gone through anything as serious as what they're going to face now."
Some of his research was first-hand. A few years ago, he and his family cruised the Mediterranean as part of a Disney promotion for the end of his "Percy Jackson" series. Many of the tour destinations end up in "House of Hades" and the other Heroes books.
But other locations exist only in myth, like Tartarus, a pit of torment deep deep in the Underworld.
"There are conflicting images of Tartarus in literature," Riordan says. "So I had to draw on my own imagination and make the scenes there as difficult and challenging as I could."
He is among the most popular and busiest writers, best known for his Percy Jackson books, featuring a dyslexic 12-year-old not unlike Riordan himself at that age. He has also completed a trilogy based on Egyptian myths, "The Kane Chronicles," and has begun a series drawing upon Norse literature that will likely debut in 2015.
Riordan, 49, has been widely praised by parents and educators for getting kids interested in ancient mythology and he has a special project planned for next summer. A former middle school teacher, he has long been dissatisfied with the anthologies of Greek myths he saw in libraries and classrooms. So he decided to write one himself and let his most famous character do the talking.
"I could never find an anthology that worked for kids, so I went back to Ovid and Hesiod and Homer and cast all the stories from snarky Percy Jackson's point of view," says Riordan, whose tentative title for the book is "Percy Jackson's Greek Gods." Disney Hyperion, an imprint of Disney Publishing Worldwide, has scheduled the book for next August.