Currently, I'm reading a fascinating Book-of-the-Month Club offering entitled The Man Who Mistook His Wife for a Hat. The author, a poetically gifted neurologist, discusses a series of case studies from the patients' point of view. The first study describes an exceptionally talented music professor who suffers from visual agnosia, a neurological disorder that inhibits one's ability to process whole images.

For example, while the professor identified and remembered specific details about someone's face-an unusual nose, mustache, or beard-he drew a complete blank when shown a picture of his brother, mother, or wife. While in the neurologist's office, he confused his wife with an adjacent hall tree and tried to lift her head from her body, thinking it was his hat. As he scanned a large National Geographic photo, his eyes would dart from one detail to another, picking up tiny features but never processing the scene as a whole.

The author, Oliver Sacks, says, "He never entered into relation with ...