Books for a 14 year old boy?

I really recommend It's Kind Of a Funny Story, by Ned Vizzini. It's not a mystery, but it's a great book. It's about this kid, Craig, who's suicidal and ends up in a psychiatric hospital for a couple of days and how he copes. Ned Vizzini is a really awesome writer, so check that out for sure. A more sci-fi/mystery oriented book you might like is I Am Number Four, which is a book revolving around a kid who is next in line to get assassinated by a secret organization from another planet.