This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines among many types of learning, at both the individual and the collective level, and absorbs the concept of adaptation into his typology of learning. It focuses on collective learning, and distinguishes sharply between many types of adaptation and a very narrow phenomenon called learning. Learning theorists in experimental psychology have long relied on a behavioral definition that corresponds in logic to the learning how variant of the hot stove example: a change in the probability of a category of response as a result of experience. The hot stove is a useful introduction to the idea of learning because it is so simple and straightforward. There is no ambiguity or dissensus about goals: almost everybody except suicidals and extreme masochists wants to avoid being burned.