The Giver Quartet by Lois Lowry (The Giver, Gathering Blue, Messenger, and Son)
[Book Review] If you haven't read this book or series yet, I want to warn you in advance that The Giver is not really a standalone story. Well, at least in my opinion it's not. (And when I'm done here you may well want to throw things at me, because my opinion of this book isn't as high as the popular consensus seems to be.)