Payment systems matter: they provide the basis for the processing and execution of the multifarious value-transfer transactions, wholesale and retail alike, that are crucial for the operation of modern, free-market economies. Less obvious–but no less pivotal–is the role that payment systems play for monetary policy and its transmission, not least in the sui generis context of the Economic and Monetary Union (EMU). The launch, in January 1999, of the Trans-European Automated Real-time Gross settlement Express Transfer (TARGET) system, the precursor of TARGET2, simultaneously with the launch of the euro, testifies to the centrality of payment systems for the implementation of the single monetary policy, and for the consolidation of the euro area money market.