The Curious Incident of the Dog In the Night-time by Haddon Mark

Christopher is 15 and lives in swindon with his father. He has asperger's syndrome, a form of autism. He is obsessed with maths, science and sherlock holmes but finds it hard to understand other people. When he discovers a dead dog on a neighbour's lawn he decides to solve the mystery and write a detective thriller about it. As in all good detective stories, however, the more he unearths, the deeper the mystery gets - for both christopher and the rest of his family.