Jonathan Livingston Seagull
by Richard Bach
Jonathan discovers that there is more to life than just surviving, but when he tries to explain this to the other seagulls, they make him an outcast, because he is too "radical."
I read this the first time as a kid and many times since--and I always gain something new from it. It has a lesson for all of us on how to really fly!
I love all of Richard Bach's books, but this was my first and will always be my favorite.