We all know a lot less than we think we do. Humans have invented countless marvels, from jumbo jets to the global economy, yet most of us can't even explain how a toilet works. How have we achieved so much despite understanding so little? Cognitive scientists Steven Sloman and Philip Fernbach argue that we overestimate the depth of our comprehension and expertise in almost every realm. We thrive by instinctively drawing on the knowledge of the people and things around us, but the illusion of individual intelligence persists. We believe we can understand complicated political or technical issues (we can't), cram endless information in our brains (we don't), and effectively make complex business decisions on our own (we won't). The Knowledge Illusion offers a better way to think about how we think. Appreciating the collaborative nature of the human mind can make us better teachers, managers, citizens, and contributing members of the community of knowledge. Book jacket.