The Host is by Stephenie Meyer. (Yes, Stephenie Meyer of Twilight fame). So, I have to mention Twilight, because you probably associate it with Meyer's name. However, I now want you to banish it from your mind because this book is written for a different audience, it has a different feel, it's on a different subject...just forget the other books altogether. Okay?
Aliens have come to Earth and humans have basically lost the battle. Once we figured out they were here, it was already too late. However, a few pockets of resistance remain, and one of the few humans left is captured and implanted with the alien Wanderer, she refuses to go down without a fight. Melanie is not ready to leave quietly and let the alien take over her body, and Melanie's emotions and memories begin to affect Wanderer (the alien) and make her question what the aliens are doing by taking over Earth and eliminating humanity.
Eventually, Melanie convinces Wanderer that they need to find Melanie's brother and her true love and make sure they are alive and well. So, Melanie and Wanderer decide to go on a quest to find a group of the resistance fighters--a quest that leads them through the desert, which may kill them in and of itself, and then, once they find the fighters, they must convince them not to kill Melanie/Wanderer, since they will know that Melanie's body has been occupied by an alien and will not believe that Melanie is still alive in there.
Still with me?
The book is a quick read, and though the first couple of chapters are confusing as you are trying to make sense of the world as it exists in the novel, it quickly sucks you in. There are many interesting conflicts--not just between the aliens and humans for survival, and not just between Melanie and Wanderer for control of the body, but interesting emotional conflicts as well. The aliens are basically nonviolent, and Wanderer can't even bring herself to hurt someone else in here own defense. Because Melanie and Wanderer share a a body, they share emotions and memories as well, and so Wanderer comes to love both Melanie's brother and the love of her life, Jared. So, once they find Jamie (the brother) and Jared, that creates interesting problems. Eventually Melanie and Wanderer come to love each other like sisters, and they must figure out what to do when it becomes apparent they cannot both live their lives in one body.
I honestly was not sure what to expect from this one, and it's not something I would typically read, but I was very pleasantly surprised. Quite good; I recommend picking it up, and like I said before, just forget anything you've heard about teenage vampires and pretend this is a different Stephenie Meyer entirely.