Forty years ago, Israeli psychologists Daniel Kahneman and Amos Tversky wrote a series of breathtakingly original papers that invented the field of behavioral economics. One of the greatest partnerships in the history of science, Kahneman and Tversky’s extraordinary friendship incited a revolution in Big Data studies, advanced evidence-based medicine, led to a new approach to government regulation, and made much of Michael Lewis’s own work possible. In <em>The Undoing Project,</em> Lewis shows how their Nobel Prize–winning theory of the mind altered our perception of reality.