Chapter 1 introduces the book’s main argument. It also defines ‘paradiplomacy’ and outlines a brief history of United States subnational relations and their key features (including trade offices, economic missions and dialogue forums), as well as states’ constitutional authority to engage in global politics. The chapter locates the book’s discussion of US states and cities’ interaction with China and Taiwan within the broader context of the existing literature on US paradiplomacy and the scholarship on US relations with divided China. It concludes by summarizing the content of the book.