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. Gerd Gigerenzer 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.