Freak the Mighty
In the beginning of the book, Maxwell "Max" Kane is a boy with low self-esteem, like his father; they are both "slow".  He lives with his grandparents Grim and Gram. Max thinks of himself as stupid and he is in a disabled class. People are afraid of him because he looks like his father, "Killer Kane," a convicted murderer.  Max sets the stage for the story by reminiscing about his time in daycare, when he was known as Kicker and Kevin, the other major character, was known as Freak.  Kevin was always different because he was small and needed crutches and then leg braces to walk. But Max respected him even back then for his death glare and thought the crutches and leg braces were cool.  Many years later when Max is in middle school, the real story begins.