THE COMMON-MARKET countries will carry out their first round of tariff reductions on January 1, 1959, and will, according to the treaty, complete tariff removals within fourteen years. The economic interdependence of the member countries will in time be much like that of regions in the United States. One big question applying to such an area is what type of monetary system would best maintain payments equilibrium between its parts. Current prospects appear to be a continuation of EPU with a strengthened harmonization of monetary policy and a possible pooling of some of the members' hard-currency reserves. The ultimate objective favored by some is reportedly a unified monetary system which might be compared with the Federal Reserve.1 It is this ultimate goal and its main alternative, rather than intermediate steps toward it, which are the subject of this paper.