Contemporary law and public policy often treat human beings as selfish creatures who respond only to punishments and rewards. Yet every day we behave unselfishly--few of us mug the elderly or steal the paper from our neighbor's yard, and many of us go out of our way to help strangers. We nevertheless overlook our own good behavior and fixate on the bad things people do and how we can stop them. In this pathbreaking book, acclaimed law and economics scholar Lynn Stout argues that this focus neglects the crucial role our better impulses could play in society. Rather than lean on the power of greed to shape laws and human behavior, Stout contends that we should rely on the force of conscience. Stout makes the compelling case that conscience is neither a rare nor quirky phenomenon, but a vital force woven into our daily lives. Drawing from social psychology, behavioral economics, and evolutionary biology, Stout demonstrates how social cues--instructions from authorities, ideas about others' selfishness and unselfishness, and beliefs about benefits to others--have a powerful role in triggering unselfish behavior. Stout illustrates how our legal system can use these social cues to craft better laws that encourage more unselfish, ethical behavior in many realms, including politics and business. Stout also shows how our current emphasis on self-interest and incentives may have contributed to the catastrophic political missteps and financial scandals of recent memory by encouraging corrupt and selfish actions, and undermining society's collective moral compass. This book proves that if we care about effective laws and civilized society, the powers of conscience are simply too important for us to ignore.