“The Measure of Darkness seems, at first, to be about the mysterious odyssey and follies of a man with a rare neurological syndrome in which the victim cannot perceive half of the world, and worse, doesn’t know he can’t perceive it. Yet, as Liam Durcan’s acutely observed, powerfully poetic prose—which can be sensitive or steely—builds to a gut-wrenching finale, we realize that this man is a metaphor for each of us and we are all haunted by the things we don’t know we don’t know.”