The Man Who Mistook His Wife for a Hat is a chamber opera based on Oliver Sacks' book of the same name. A true story, it takes the form of a neurological case-study; Dr. P, a professional singer and music professor, suffers from visual agnosia — an inability to recognize or make sense of what he sees. The opera describes two consultation sessions during which the other two characters, the neurologist (Dr S) and the patient's wife (Mrs P), penetrate the mystery of Dr P's symptoms through conversations and tests. Beyond that the opera possesses no story and reaches no great climax or conclusion. However there is drama in quantity, supplied largely by the characters' reactions and responses to one another. In its wistful way it is also often hilariously funny.

If there had ever been any doubt about the matter, The Man Who Mistook His Wife for a Hat firmly secures Michael Nyman as a composer of substance and significance. Although the score blatantly revels in its prosaic ordinariness, the effect has been calculated to avoid superficial theatricality, to underline the ridiculousness of the situation, to instill into the action a tension, a nervous energy, that sustains interest through an hour of what is virtually uninterrupted dialogue. Ludicrously simple, as Nyman's score appear at first, by the end one has the impression of a score of unusual power and pathos.