At eighteen months, Ashley Ruben still didn't talk. She wouldn't respond when her name was called; she didn't appear to hear either. She fixated on tiny pieces of dirt and ate only crunchy foods. She was enveloped in a thick fog-impenetrable by everyone except Barney the Dinosaur. She worked puzzles like a kindergartener and was computer-savvy before she was two years old. Her mother's late-night searches on the Internet hinted at a reason for her lack of engagement with the outside world. And then a developmental specialist confirmed it: autism, a diagnosis that shook the foundation of a...