Book excerpt: The question as to the choice of the optimal exchange rate system to be adopted among MERCOSUR countries becomes critical if MERCOSUR states attempt to go further along the path of increasing their trade flows of goods and services. The study contributes to filling this gap by providing some alternative answers to this issue. The analysis has been based on three pillars: a theoretical review of exchange rate systems: a review of the European experience; and an analysis of the Latin American experience.