The study of American grand strategy is dominated by historians who describe former grand strategies, and international relations scholars who prescribe what it should be. In contrast to either approach, this chapter has three components: First, it identifies the national cultural influences, the key elements of the mythic “American Creed,” that provide the emblematic foundations of contemporary American grand strategy. Second, it describes the historical evolution of the institutional mechanisms that both formulate and implement American grand strategy, and how those institutions actually operate in the modern era. And third, relating these elements, it explains the parameters of American grand strategic planning—how it operates in practice. This includes an overt reliance on military instruments and a conscious sensitivity to field conditions in implementation that may undermine the most grand strategic designs. The chapter concludes by contemplating the prospects for continuity and change in American grand strategy.