i just finished reading "the ringmaster's daughter" by jostein gaarder (a norwegian author, who wrote "sofie's world").
the main character of this book *"must"* have some kind of np diagnosis - i'm thinking asperger syndrome!
:D

Ender's Game - by Orson Scott Card
The Chrysalids - by John Wyndham

It could be argued that Ender from the first book has ADD. Both books describe a subclass of people who are different, and in some ways better, than those around them and aren't necessarily appreciated for their differences.