This introductory article discusses the new field of the sociology of finance. Finance is a major force in contemporary economies and societies. Yet few social scientists outside of economics have addressed the phenomenon before the financial crisis of 2007–09. The crisis prompted a hard look at the financial system that was created since the 1980s, an examination undertaken by various social science disciplines. Sociology tends to look at finance broadly as an action system within the framework of the institutions and organizations in which financial activities take place. Sociologists also ask questions about the internal operation of the financial system, and they often ask questions about its effects. Both types of questions tend to go beyond the typical questions of investors and analysts. The study of finance from a behavioural social science perspective is an emergent interdisciplinary field in its own right that has started to provide answers to such questions. This book brings together the emerging perspectives and micro- and macro-level concerns of this field, and it maps out directions in which the social science analyses of finance will need to go in the future.