This entire book was just endlessly fascinating to me. It's all about how traumatic insults to the skull and brain, whether by physical force or insidious viruses, affect our physical abilities and thoughts.
Kean expertly weaves storytelling about particular brain trauma patients with carefully explained science. I knew of a few of the conditions discussed, but certainly not in the detail Kean devotes. He explains the process of how damage occurs and then why that damage can cause conditions like kuru disease, phantom limbs, aphasia, hallucinations. He even touches on the history of scientists and doctors attempting to local the home of the soul in the brain.
Kean opens each section with the story of a particular person (or group of people) who has experienced an injury to the brain, and then explains how the doctors of the time attempted to help that victim with their contemporary knowledge. Each story is like a mini-mystery; you receive just enough information to understand the situation and then want to keep reading in order to solve/understand the process along with the doctors or scientists. I don't want to give them all away, but one example is how the cannibals in Papua, New Guinea were felled by kuru; in the end it wasn't because they cannibalized their dead ("eating brains isn't inherently deadly") but rather but rather "the bad luck of eating patient zero."
Kean explains why even people born without limbs can experience phantoms, blind people will still respond to smiles or scowls or yawns without even understanding why, how reading changes our brain, why some victims of brain damage can write perfectly well but cannot read (not even the sentence they just wrote), that brains vary from person to person as much as faces do, and how a set of (still living) twins share a conjoined brain and so can do things like taste what's in one another's mouths and yet retain distinct individual thoughts and preferences.
Witty, informative, a bit scary. To consider how vulnerable and yet also how resilient our brains are, is just fascinating.