Diagnosed with multiple sclerosis shortly after his daughter's birth, the author compares the joy, heartbreak, and anxiety of his own neurological decline with his daughter's flourishing brain activity.

The inward empire: the marrow of the skull: the birth of neurology and a basic guide to the brain -- Lost: the man who couldn't open a door: a guide to proprioception -- Help me: Phineas Gage, the most famous neurological patient in history -- The Frankenstein dance: the first recorded case of MS -- The dead teach the living: "I only observe, nothing more": Jean-Martin Charcot and the discovery of MS -- The ghost on the green: Myelin, the mysterious--and misunderstood--substance at the heart of MS -- Hyde: the viking gene, the equator, and vitamin D: the hunt for the possible causes of MS -- Inside the tent: the art of diagnosis -- The explorers' club.