Ten papers consider the difficulty that emerging markets encounter when attempting to borrow abroad in their own currencies--a difficulty sometimes referred to as "original sin" since it seems like an inherited burden almost unrelated to policies of the particular government trying to borrow money; analyze the consequences of original sin for the performance and prospects of emerging markets; and investigate the underlying sources of the problem. Examines how the extent of a country's foreign-currency denominated external debt impacts the stability of output, volatility of capital flows, management of exchange rates, and country credit rating; whether original sin must lead to bad macroeconomic outcomes; a fiscal perspective on currency crises and original sin; original sin, balance-sheet crises, and the role of international lending; the evolution of external debt denominated in domestic currencies in the United States and the British dominions, 1800-2000; exchange clauses and European foreign lending in the nineteenth century; why emerging economies borrow in foreign currency; why countries borrow the way they borrow; the mystery of original sin; and the road to redemption.