The Eye of the Spirit is in the same vein as the famous "Man who mistook his wife for a hat" Sacks recounts some cases of neurological deficiencies or failures he encountered and treated (all true, and is based on medical research cited), but with a sense of narrative, personal involvement and humanity that make these "clinical case" fascinating to discover and read more comical (case prosopagnosia, or that overflowing woman activity after a stroke) to the most emotional, especially the final chapters on cancer which affected the author's eye itself. You learn a lot about the functions of our brain, and we also learn to live, although we do.