Bad Twin — a slickly marketed tie-in novel to ABC’s hit television show Lost that is being touted as the last novel written by a popular mystery writer who disappeared on Oceanic Flight 815 — is a terrific pulp noir mystery. While the novel’s plotline (a struggling New York City private eye accepts a lucrative assignment to track down a real estate magnate’s wayward identical twin, only to be sucked into an unfathomably deep conspiracy) has no obvious links to the television show, there are countless tantalizing references throughout that will have hard-core fans of Lost speculating for months. (For example, the wealthy man looking for his brother is named Clifford Widmore, and a prominent organization renting space in his flagship building is the Hanso Foundation.) There are numerous references to John Locke, numerology, and purgatory, which many fans have speculated is actually where the show is set: The characters are all dead and working their way toward redemption. An anagram for the fictional author Gary Troup is, by the way, Purgatory.