Book excerpt: Much of the science of public opinion focuses on individuals, asking if they perceive or misperceive and why. Often this science will emphasize misperceptions and the psychological processes that produce them. But political debates have outcomes in the aggregate. This Element turns to a more systematic approach, emphasizing whole electorates and examining facts through a dynamic lens. It argues public opinion will converge toward truth over time and frequently finds correct views of facts grow stronger under information flow, while misperception recedes.