A couple of years ago, I reviewed the three paperback novels published to tie into Lost. Set on the island, and featuring other passengers of Oceanic Flight 815, they were a failure both as standalone novels and as t.v. show tie-ins.
I wasn't expecting much, then, from Bad Twin. This is the book written by the fictitious Gary Troup, a passenger on Flight 815 who died in the crash. There's a scene (maybe two) in the show where Sawyer is reading a book manuscript and announces that it's pretty good--that's this book, and I have to agree.
It starts with a note "from the editors" mourning Troup's presumed death aboard the plane, and includes some correspondence between Troup and the editors that reveals he had a thing for Cindy, the flight attendant who is in several episodes of the show. The book itself is an homage to hard-boiled private detective stories, as down-on-his-luck P.I. Paul Artisan gets hired by the wealthy Clifford Widmore to find his missing brother. Artisan gets drawn into the usual web of lies and deceit, but the story is nicely paced and there's a solid mystery underneath.
Even though the name Widmore is used, and there are references to the Hanso Foundation, Paik, and other elements of the show, the book doesn't tie directly into the island or the main cast. It does, however, include several of the themes that came to the forefront in the final season of Lost: twin brothers, good and evil, the nature of fate, etc. Although the book came out in 2006, it makes me think the show's producers really did know where they wanted the show to go. As a standalone mystery or a t.v. tie-in, this one is worth getting.