Cathy Vickers is a popular girl. And that's just as Running Press wants it. The heroine of the Perseus imprint's first YA novel, who currently has more than 500 friends on her MySpace page and 100,000 copies of her book in print, is at the center of an innovative and aggressive marketing campaign that includes a trailer in movie theaters. The decision to plug the book, which came out September 12, in movie theaters came after Running Press saw the 49-second trailer authors Sean Stewart and Jordan Weisman made for YouTube. In it, a female narrator (presumably Cathy) makes a call to the police reporting her diary's been stolen, she's been kidnapped, her boyfriend's missing and her friend was shot. The advice from the disinterested cop—"try a bookstore"—slyly communicates that the novel is, in fact, Cathy's missing diary.

Craig Herman, v-p of marketing and publicity at Running Press, said the spot was so well done that his team wanted to move it beyond the DIY aesthetic of YouTube. Now, throughout December, it will run as a trailer, alongside movie previews, in 20 theaters across the country. Herman, who believes this is the first time a publisher is trying this sort of theatrical promotion, wouldn't provide a figure on the cost of the outreach, but said it's cheaper than prime-time TV advertising. (David Steinberger, president of Perseus, said the overall campaign for Cathy's Book is "very much in line, from a dollar standpoint, with what we would typically spend for a book.")

Running Press's grassroots, viral push for the book, which includes a profile for Cathy on MySpace, has taken at least one pleasantly unexpected turn. Two teenagers posted their own Cathy's Book trailer on YouTube. In it, they pick up the book at Target, call the number on the cover—the book's subtitle reads: If Found Call 650-266-8233—and giggle at the message. (It's not clear if they realize they've been duped into action by a smart marketing campaign.) The young filmmakers do leave the book on the shelf, though, rather than bringing it to the register.

Cathy's Book will also be advertised in malls during the holiday season and Running Press is toying with the idea of doing an iPod giveaway for the book. (The house has already done a contest around Motorola Razr phones.)

So is it working? According to Nielsen BookScan, Cathy's Book has sold 4,000 copies. Steinberger said that number is deceiving because the title is selling in a number of major accounts not tracked by BookScan, including Wal-Mart. (He declined to say how many copies the book has sold, or specify which other non-BookScan outlets are contributing to sales.) Also encouraging is the number of phone messages the fictitious Cathy has been receiving; according to Steinberger, she's gets up to 80 calls a day. Whether that makes for a clogged inbox or a future bestseller remains to be seen.