The European Community is negotiating a new treaty to establish the constitutional foundations of an economic and monetary union in the course of the 1990s. This study provides the only comprehensive guide to the economic implications of economic and monetary union. The work of an economist inside the Commission of the European Community, it reflects the considerations influencing the design of the union. The study creates a unique bridge between the insights of modern economic analysis and the work of the policy makers preparing for economic and monetary union.