"Cathy's Book : if found call (650)266-8233" by Sean Stewart and Jordan Weisman. Running Press, 2006.

Cathy, a senior in high school, journals about events that happen to her after she starts dating Victor. He suddenly dumps her, and Cathy and her best friend, Emma, do their detective thing to find out why. They become involved in a dangerous hunt for who he really is, murder, kidnapping, and laboratories, with a twisted, surprise ending.

The jacket blurb indicates that the authors are PC Game creators (MechWarrior, I Love Bees), and invites readers to "Read. Explore. Investigate. Examine the Clues. Call the phone numbers. Access the websites. And when you're done, you'll know that the teen novel will never be the same again."

I didn't explore, investigate, or call the phone numbers, but if anyone does, I invite you to post what you find out in a comment.

(Cross Posted at grandCENTRAL)