THE ECHO MAKER by Richard Powers

On a winter night on a remote Nebraska road, twenty-seven-year-old Mark Schluter has a near-fatal car accident. His older sister, Karin, returns reluctantly to their hometown to nurse Mark back from a traumatic head injury. But when Mark emerges from a coma, he believes that this woman—who looks, acts, and sounds just like his sister—is really an imposter. When Karin contacts the famous cognitive neurologist Gerald Weber for help, he diagnoses Mark as having Capgras syndrome. The mysterious nature of the disease, combined with the strange circumstances surrounding Mark’s accident, threatens to change all of their lives beyond recognition.