With such compelling and provocative novels as Red Planet Blues, FlashForward and The WWW Trilogy, Robert J. Sawyer has proven himself to be "a writer of boundless confidence and bold scientific extrapolation" (New York Times). Now, the Hugo and Nebula Award-winning author explores the thin line between good and evil that every human being is capable of crossing...Experimental psychologist Jim Marchuk has developed a flawless technique for identifying the previously undetected psychopaths lurking everywhere in society. But while being cross-examined about his breakthrough in court, Jim is shocked to discover that he has lost his memories of six months of his life from twenty years previously--a dark time during which he himself committed heinous acts. Jim is reunited with Kayla Huron, his forgotten girlfriend from his lost period and now a quantum physicist who has made a stunning discovery about the nature of human consciousness. As a rising tide of violence and hate sweeps across the globe, the psychologist and the physicist combine forces in a race against time to see if they can do the impossible--change human nature--before the entire world descends into darkness.