 Markets are institutions in which individuals or collective agents exchange goods and services. They usually use money as a medium of exchange, which leads to the formation of prices. Markets can be distinguished according to the goods or services traded in them (e.g., financial markets, housing markets, labor markets), according to their scope (e.g., regional, national, international markets), or according to their structure (e.g., competitive markets, oligopolistic markets, monopolistic markets). From a normative perspective, markets are of interest for a number of reasons: various arguments for and against markets relate to central questions of social and political philosophy. In addition, markets depend on, and in turn influence, many other institutions and aspects of social life. They thus co-determine the ways in which values such as liberty, justice or solidarity can be realized. Questions as to which markets, for what goods, can be defended by normative arguments, and how they relate to other institutions, are therefore at the core of thinking about a just society.