A critical history of the US dollar’s dominance in the world economy—and what has kept China’s currency from overtaking it. The dollar is the primary currency of the world economy. With China now rivaling the United States on the world stage, a critical question hangs in the balance: will the Chinese renminbi challenge the status of the dollar and, in doing so, deprive America of its “exorbitant privilege”? In Greenback Empire , Ho-fung Hung offers a powerful account of why, even as American shares of global production, ownership, and trade continue to decline, its currency has retained the support of governments and investors around the world. For six decades, Hung shows, the dominance of the dollar has rested on the security umbrella that the US offers to the world’s wealthiest countries—including oil producers. To these countries, support for the value of the dollar is tantamount to maintaining US protection. While China has become a serious geopolitical and economic rival to the US, the Chinese state’s airtight control of its financial system has delayed the free trading of the renminbi, limiting the currency’s internationalization. In short, the same strategy that engineered growth in China’s economy is restraining its currency's rise in opposition to the dollar. Hung’s Greenback Empire is an essential history of the dollar’s prowess, indispensable for understanding the future of the global monetary system.