The Man Who Mistook His Wife for a Hat is a book by Oliver Sacks describing the case studies of some of Dr. Sacks's patients. The case study that gives the book its title describes the study of a man with visual agnosia. It became the basis of an opera by Michael Nyman, composed in 1986.

The other essays in this book include:

• "The Lost Mariner," about Jimmie G., who has lost the ability to form new memories due to Korsakoff's syndrome. He can remember nothing of his life since his demobilization at the end of WWII, including events that happened only a few minutes ago, and must struggle to form an identity. The main character of the film Memento has a similar condition, and struggles to identitify a certain "John G." or "Jimmy G."
• "The President's Speech" - about a ward of aphasiacs and agnosiacs listening to a speech given by President Reagan. Each group saw flaws in the president's content and presentation respectively, flaws which escaped the notice of 'normal' people. This essay gives insight into techniques of propaganda.
• "The Disembodied Lady" - a unique case of a woman losing her entire sense of proprioception.
• "The Twins"- about autistic savants. Dr. Sacks tries to connect with twin brothers by joining their game of finding very large prime numbers. He cheats and uses a book; neither of them can read or even do multiplication. They instantly count 111 dropped matches simultaneously noticing that 111 is three 37s. This event, with toothpicks in place of matches, and other of Dr. Sacks' observations on autistic savants, were used in the film Rain Man, starring Dustin Hoffman.