The Man Who Mistook His Wife for a Hat and Other Clinical Tales is a 1985 book by neurologist Oliver Sacks describing the case histories of some of his patients. Sacks chose the title of the book from the case study of one of his patients who has visual agnosia, a neurological condition that leaves him unable to recognize faces and objects. The book became the basis of an opera of the same name by Michael Nyman, which premiered in 1986. The book comprises twenty-four essays split into four sections ("Losses", "Excesses", "Transports", and "The World of the Simple"), each dealing with a particular aspect of brain function. The first two sections discuss deficits and excesses (with particular emphasis on the right hemisphere of the brain), while the third and fourth sections describe phenomenological manifestations with reference to spontaneous reminiscences, altered perceptions, and extraordinary qualities of mind found in people with intellectual disabilities. In addition to describing the cases, Sacks comments on them, explains their pathophysiological background, discusses potential neuroscientific implications of such cases and occasionally makes reference to some psychological concepts, such as the soul, id, ego, and super-ego. Content The individual essays in this book include: "The Man Who Mistook His Wife for a Hat", about Dr. P., a singer and music teacher who has visual agnosia. He perceives separate features of objects, but cannot correctly identify them or the whole objects that they are part of. At first he supposes that diabetes has affected his vision, but an ophthalmologist suspects a neurological problem and refers him to Sacks. As he leaves Sacks' examination room during his first visit, he momentarily grabs his wife's head, supposing it to be his hat. Unable to treat Dr. P.'s problem, Sacks encourages him to focus on his musical interests, which remain intact. "The Lost Mariner", about Jimmie G., who has anterograde amnesia (the loss of the ability to form new memories) due to Korsakoff syndrome acquired after a rather heavy episode of alcoholism in 1970. He can remember nothing of his life since the end of World War II, including events that happened only a few minutes ago. Occasionally, he can recall a few fragments of his life between 1945 and 1970, such as when he sees "satellite" in a headline and subsequently remarks about a satellite tracking job he had that could only have occurred in the 1960s. He believes