Following in the footsteps of his hero Sherlock Holmes, when Christopher Boone discovers the dog dead on the lawn, he sets out to find out who did it. But Christopher's search is no ordinary one; Christopher can recall numbers, will feel safe for a day when he sees three or four or five red cars in a row but finds emotions near-impossible to unravel. To find the truth about the dead dog presents the need to understand some complex emotions and also propels Christopher into looking more carefully into his own family and their relationships. Mark Haddon's telling of Christopher's unpredictable response to them is original, kind, disturbing and profoundly moving.

Christopher Boone is a detective. Christopher is fifteen and has Asperger's Syndrome. He knows a great deal about maths and very little about human beings. He has never gone further than the end of the road on his own, but when he finds a neighbour's dog murdered he begins a terrifying journey which will turn his whole world upside down.