Xenocide by Orson Scott Card is the third book in a science fiction series about a man named Ender. The first two books, Ender's Game and Speaker For the Dead were both good (although Ender's Game was my favorite). Xenocide, however, was not so good. There are some interesting characters, but the plot goes way out into left field, and I found myself losing interest about halfway through the book.
Here's a link to my full review.