Keynesian ideas have been central to the major debates about economic policy and macroeconomic theory for the larger part of the twentieth century. This holds particularly for the age of economic prosperity and sustained growth which followed the period of reconstruction after World War II, before accelerating inflation and the first oil price shock brought an end to what is widely considered as “the age of Keynes”. At the same time, differences in economic and political conditions across nations are the reason how and why some countries embraced Keynesianism, while others did not. In the reception and application of Keynesian economics, there are considerable differences between European countries, with respect to economic theory and economic policy, as well as time.