How and why is nationalization central to the politics of resource-rich countries? This chapter opens with a review of current theories on natural resource wealth and nationalization in political science, economics, and public policy, and then describes why existing theories are unable to answer the questions this book seeks to answer. With these questions in mind, this chapter presents the book’s central theory of why leaders nationalize and how leader survival shapes and is shaped by the choice of nationalization. After describing empirical implications of the argument, the chapter offers initial evidence to support these claims in the form of exploratory case studies of Iran and Iraq. In Iran, the shocking collapse of the Shah in 1979 defied the West’s notion of the “island of stability” in the tumultuous Middle East. In Iraq, the fall of the Hashemite monarchy in 1958 ushered in a decade of instability until the unexpected Ba’athist consolidation in 1968, when Hassan al-Bakr established a 35-year single-party dictatorship. These are precisely the types of outcomes in which the book’s theory predicts nationalization should affect the rise and fall of dictatorships.