Where do new ideas come from? What is social intelligence? Why do social scientists perform mindless statistical rituals? This vital book is about rethinking rationality as adaptive thinking: to understand how minds cope with their environments, both ecological and social. The author proposes and illustrates a bold new research program that investigates the psychology of rationality, introducing the concepts of ecological, bounded, and social rationality. His path-breaking collection takes research on thinking, social intelligence, creativity, and decision-making out of an ethereal world where the laws of logic and probability reign, and places it into our real world of human behavior and interaction. This book is accessibly written for general readers with an interest in psychology, cognitive science, economics, sociology, philosophy, artificial intelligence, and animal behavior. It also teaches a practical audience, such as physicians, AIDS counselors, and experts in criminal law, how to understand and communicate uncertainties and risks.