This book analyses the interaction of monetary and fiscal policies in the Economic and Monetary Union in order to determine whether any form of cooperation between policymakers is welfare enhancing and can be sustained. The strategic relationship between policymakers in the EMU is analysed within the framework of a general equilibrium model with price rigidities. In this model, fiscal policy is assumed to have positive demand spillovers and the assumption of nominal rigidities, together with that of rational expectations, creates a problem of time- inconsistency involving the formulation of optimal policy decisions. This analysis shows that the coordination of fiscal policies among countries can be counterproductive, in particular when policymakers lack the credibility to pursue optimal policies. The implications of uncertainty on the strategic interaction of macroeconomic policies are also examined. Uncertainty is modelled by introducing the possibility of stochastic productivity shocks. It is concluded that, under some circumstances, uncertainty can make central banks more effective in the implementation of monetary policy.