At our house right now, my tweens are racing through Andrew Klavan's books. Here's what my daughter says:
Crazy Dangerous is a well-written thriller. Sam is a regular boy who finds himself in extraordinary circumstances. He just wants to be a normal kid, but not pushed around anymore. Jennifer is a school mate with some type of mental illness. She talks crazy and hallucinates. This shouldn't impact Sam but it does because the thugs that are trying to mess up Sam's life are messing with Jennifer, too. Sam has a strong desire to protect Jennifer and stop whatever she's facing.
This was the first Andrew Klavan book I read. I enjoyed it so much, that I've now raced through the Homelanders series. The author's books are great because they are action-packed. They are impossible to put-down. And are perfect for kids who like to read stories about heroic struggles.
My 8.5 year old son likes his books because they are action-packed and heroic. The kid is in trouble the whole way through the book. My husband enjoyed the series because it captured all the angst of the teen years but equipped the main character for the struggles he would face.