Book of the Day: The Ruins : a novel by Scott Smith

Just saw this move last night and I enjoyed it, but heard that the book is much, much better. What do you think? Here's the description from Publishers Weekly, "Four American friends on vacation in CancĂșn, Mexico—Jeff, Amy, Eric and Stacy—meet a German tourist, Mathias, who persuades them to join his hunt for his younger brother, Henrich, last seen headed off with a new girlfriend toward some ruins. The four soon regret their impulsive decision after they find themselves lost in the jungle and freaked out by signs that they're headed for danger. Smith builds suspense through the slow accretion of telling details, until a deadly menace starts taking its toll, leaving the survivors increasingly at each other's throats."