Taking into account the sheer ubiquity and ordinariness of deception, this interdisciplinary work moves away from the cut-and-dried notion of duplicity as evil and illuminates the ways in which deception can also be understood as a adaptive response to the demands of living with others. The book articulates the boundaries between unethical and adaptive deception demonstrating how some lies serve socially approved goals, while others provoke distrust and condemnation. Throughout, the volume focuses on the range of emotions--from feelings of shame, fear, or envy, to those of concern and compassion--that motivate our desire to deceive ourselves and others.