The dominance of the American dollar was never inevitable. It was engineered - first in a New Hampshire resort hotel in 1944, where forty-four nations agreed to anchor the postwar monetary order to a single currency, and then again in the early 1970s, when the collapse of gold convertibility threatened that dominance until a series of bilateral agreements with Saudi Arabia quietly replaced one foundation with another. This book traces the full arc of dollar hegemony from the Bretton Woods conference through Nixon's 1971 suspension of gold convertibility and into the petrodollar arrangements that restructured global energy trade around American financial infrastructure. Drawing on Treasury Department archives, Federal Reserve records, diplomatic cables, and the memoirs of key architects, it examines the deliberate institutional choices that transformed the dollar from a postwar convenience into the structural spine of the global economy. The analysis moves beyond monetary theory to reveal the geopolitical dimensions of currency power - how dollar dominance shaped alliance structures, constrained the sovereignty of debtor nations, and created the conditions under which American foreign policy could operate with a financial latitude unavailable to any other state. It also examines the sustained challenges to that dominance, from the European monetary project to OPEC pricing experiments and the gradual emergence of alternative reserve currencies. For readers seeking to understand how money became an instrument of geopolitical power, this book offers a rigorously sourced account of the system's construction, its contradictions, and its enduring consequences.