Laura Mature teens and up. Maybe 14 at the very lowest end, but the language is strong and the themes are very strong. There's a lot of hate language (think "Gran Torino" style), and I think it requires a certain level of critical thinking to understand the context of the story.
Nicole Teenagers to adults. While there are children (11 year old) characters in the book, some parts may be hard to grasp for young adults (they took double or sometimes triple readings for me to grasp and I'm 32).