The euro is the only major currency to be created in the 20th century; it now stands on the brink of becoming one of the world's two reserve currencies in the 21st century. The euro's use and development shape the entire agenda for ever-closer union in Europe and for transatlantic relations. As the currency bearing the brunt of the US dollar's decline from its overvaluation of the late 1990s, the euro's value and management is critical to the successful adjustment of international imbalances. And as a long-run competitor and collaborator with the dollar, the euro creates the potential for a bipolar international monetary system, offering unprecedented challenges and opportunities to economic policymakers. The papers and commentaries in this book explore the euro's international role, its record thus far, and its future.