During recent decades, mobility of people and capital has increased dramatically, for reasons both political and technological. Common markets, open borders, air traffic, and the Internet have made it faster and less expensive to change places—and jurisdictions. As a result, law itself has increasingly become a good that is subject to the market mechanism. Not only is it easier to move; people are also given more and more opportunities to choose which legal rules shall apply to their company, their contract, their marriage, or their insolvency proceedings. States grant these opportunities, and they respond to them by competing with their legal products and services against other suppliers for the favour of demanders. This chapter introduces the term ‘regulatory competition’ and lays out the contours of the book as a whole as well as the contents of its individual chapters.