"I speak the truth, not so much as I would, but as much as I dare...."-- Montaigne "All cruel people describe themselves as paragons of frankness.'" -- Tennessee Williams Truth and deception--like good and evil--have long been viewed as diametrically opposed and unreconcilable. Yet, few people can honestly claim they never lie. In fact, deception is practiced habitually in day-to-day life--from the polite compliment that doesn't accurately relay one's true feelings, to self-deception about one's own motivations. What fuels the need for people to intricately construct lies and illusions about their own lives? If deceptions are unconscious, does it mean that we are not responsible for their consequences? Why does self-deception or the need for illusion make us feel uncomfortable? 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. Providing an interdisciplinary exploration of the widespread phenomenon of lying and deception, this volume promotes a more fully integrated understanding of how people function in their everyday lives. Case illustrations, humor and wit, concrete examples, and even a mock television sitcom script bring the ideas to life for clinical practitioners, behavioral scientists, and philosophers, and for students in these realms.