This is the first book to describe the entire developmental history of the human aspects of economics. The issue of "self-interest" is discussed throughout, from pre-Adam Smith to contemporary neuroeconomics, representing a unique contribution to economics. Though the notion of self-interest has been interpreted in several ways by various schools of economics and economists since Smith first placed it at the heart of the field, this is the first book to focus on this important but overlooked topic. Traditionally, economic theory has presupposed that the core of human behavior is self-interest. Nevertheless, some economists, e.g. recent behavioral economists, have cast doubt on this "self-interested" explanation. Further, though many economists have agreed on the central role of self-interest in economic behavior, each economist's positioning of self-interest in economic theory differs to some degree. This book helps to elucidate the position of self-interest in economic theory. Given its focus, it is a must-read companion, not only on the history of economic thought but also on economic theory. Furthermore, as today's capitalism is increasingly causing people to wonder just where self-interest lies, it also appeals to general readers.