"The Curious Incident of the Dog in the Night Time," by Mark Haddon. Doubleday, 2003.
Told from the viewpoint of 15 yr. old Christopher, who has a form of autism, the mystery of who killed his neighbor's dog morphs into another mystery altogether. In systematically "detecting" the circumstances of the dog's death, Christopher actually tells two stories: the story of his struggle to cope in a "normal" world, and the story of the break-up of his parents' marriage.
This book seems to have a big impact on each person who reads it. It is tragic, funny, pathetic, and insightful. I couldn't put it down.