Sovereign Debt (SD) is a subject of pervasive interests considering its size and that keeps on growing unabated. The book defends a contractual approach to manage SD default and restructuring against a trend fostered by international organizations and groups of interests that are trying to introduce a public solution akind to a bankruptcy procedure for the embattled Sovereigns. It carefully debunks the arguments of those that defend the bankrucpty approach, and shows with a palette of arguments that the contractual approach streamlined with new clauses and incorporating some elements from the ongoing reform of the international financial architecture is the best alternative to handle it efficiently. Contract law, enhanced via the newly generated transnational private law on the field --that becames a sort of lex mercatoria debitoris soberanis--, is analyzed and applied. Solutions are tested and confirmed against the leading methodological approaches, L&E, game theory and a touch of the critique. Although the book is writen from a technical legal perspective it frames the legal solutions within the economic and political background, as SD is at the core of both the monetary system and the payment systems.