On a July evening 22 years ago, 20-year-old Terry Wallis climbed into a pickup truck with two friends and rode off down a rural Arkansas highway. He never came back -- or, more precisely, he never came back the same. The truck went off a bridge. One of Wallis' friends was uninjured; the other died. Wallis barely made it. First, he was in a coma, then in what doctors called a "vegetative state," and then in what they called a "minimally conscious state." He was paralyzed from the neck down and couldn't talk. His parents assumed legal guardianship from his...