Helen Thomson's Unthinkable: An Extraordinary Journey Through the World's Strangest Brains.

Editor's Note: Unthinkable's author, a British neuroscientist, tracked down nine people with rare brain disorders to tell their stories. From the man who thinks he's a tiger to the doctor who feels the pain of others just by looking at them to a woman who hears music that's not there, their experiences illustrate how the brain can shape our lives in unexpected and, in some cases, brilliant and alarming ways.