Although Cathy's Book may not, as its press materials note, be the start of a new genre in YA fiction, it's a pretty inventive take on the category. The title, which is due out from Running Press in September, is a kind of Choose Your Own Adventure for the 21st century kid. While the premise is not so groundbreaking--a teenager, suddenly dumped by her boyfriend, is drawn into a mystery when she tries to figure out where the relationship went wrong--the book references Web site addresses and phone numbers in its text that readers can actually call and log onto. That the numbers and URLs are all live--recordings point to eerie mystery-deepening information about the characters and the plot--makes the book that much more fun.

Included with "an evidence package" that has everything from a birth certificate to a strange family photo, the book immediately struck Perseus Book Group president, David Steinberger, as something special. But Steinberger said he didn't know how big a hit he might have until the title started a string of foreign rights bidding wars, something the publishing veteran said he has rarely, if ever, seen for a debut book like this.

Written by a fantasy novelist and a game developer, Cathy's has already drawn well over $100,000 in foreign rights for Perseus with auctions happening everywhere from Italy to Germany to Japan."To have a book by authors that don't have an established track record in this category and that was not acquired in a big auction get the kind of reaction we've gotten here, well, it makes us feel like we have something very special," Steinberger said. The feeling about the book is special enough that Running Press is upping the initial printing and has signed authors Sean Stewart and Jordan Weisman to a second book.