This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book reviews the debate on the decline of United States (US) hegemony. It aims to develop the nature of hierarchical regional orders, focusing on the Western Hemisphere. In order to contextualize the academic discussion, the book looks at the initial conditions around which the debate has revolved, and considers the means through which Washington achieved hegemonic status in the aftermath of World War II. It discusses the notion of power as an attribute, then takes on the understanding of power as a relation, in both its “thin” and “thick” variants, and deals with the operationalization issues that come about when doing power-centered empirical analysis. The book also considers US’ economic statecraft toward Mexico in an analogous fashion. It also discusses US’ statecraft toward South America.