The truest empathy is to inhabit a hindrance, to rent it out and show others a place they would otherwise never imagine. Haddon’s accomplishment is of a high order. Autistic Christopher, struck by the death of his neighbor’s dog, devises the necessary mental mathematics to investigate the crime. His feelings are deductive, probative, literal, but Haddon occupies this crawlspace so effectively that Christopher blooms into life. Few reach the pure intelligence of such a dark (and comic) chamber. Haddon does. It’s a monumentally spiritual accomplishment.