Phantoms In The Brain - V. S. Ramachandran.
Probably
the most fascinating piece of popular science writing I've ever read. It's written by an eminent neurologist and discusses some of the weirder things that can go wrong with the wiring of the human brain in an extremely accessible and charming way.
Each chapter is like an episode of House, except it's both real and more bizarre and otherworldly than anything House ever tackled.
READ IT NOW.