I'm not sure this book actually qualifies as underrated. After all if spent several weeks on the bestsellers list. But I think in comparison to the author's other books, it is almost never talked about. The book in question...
Twilight is obviously everywhere, but while I think people have her of Stephanie Meyer's other book, to me it seems rare that people have actually. I posted a review about 2 years ago after the second time I read it. While I don't think I've read it a third time yet, I love it just the same.
If you hated Twilight (or even if you loved it), I really think you should give this one a chance. In my opinion, while I loved Twilight, I think this is so much better. I did hear they recently signed a movie deal for it, so I'm hoping as the movie gets closer this one gets on more people's radar.
Have you read The Host? Were you a fan? And what do you consider to be the most underrated book?