Remembrance of Earth's Past - Book #3
by Cixin Liu
This is the final book of the trilogy, and boy is it a doozy. It's a bit more depressing than the others. Humanity has been kicked to the curb and then stomped on, beaten, and left for dead. It really takes a pessimistic view of our future with alien life.
That said, I thoroughly enjoyed it and could barely put it down throughout. The ending was surprising and a bit of a let down, but it doesn't really detract from the overall story.
If you enjoyed the first two books, you owe it to yourself to pick this one up and finish the story!