In this interview excerpt, Niels Thygesen, Head of Monetary Division and Studies at the Organisation for Economic Cooperation and Development (OECD) in Paris from 1971 to 1973, Adviser to the Governor of the Danmarks Nationalbank from 1973 to 1983 and Chairman of the Danish Economic Council from 1983 to 1985, discusses the creation and operation of the European Monetary System (EMS) from 1979 onwards, especially the introduction of the European Currency Unit (ECU). He also refers to the increasing interest among the Member States of the European Communities in the 1980s in progressing towards an economic and monetary union.