The Man Who Mistook His Wife For A Hat
Dr. P. was a musician of distinction, well-known for many years as a singer and a music teacher. However, Dr. P. began acting strangely. Sometimes a student would present himself, and Dr. P. would not recognize his face. But then Dr. P. also began to see faces when there were no faces to see. When in the park he might pat the heads of fire hydrants and parking meters, mistaking them for the heads of children.
Finally, Dr. P. went to see Dr. Oliver Sacks for help. After the examination Dr. P. looked around for his hat. He reached out and took hold of his wife's head, trying to lift it off and put it on his head! That explains the title of Sacks's book in which he related this true story: The Man Who Mistook His Wife for a Hat.