vii Foreword It is fair to say that payment systems have become one of the most vibrant areas of reform, be it in terms of policy, technology or products. This is shown by the rapid pace of change we observe in national and international payment systems around the world. One of the reasons for this reform process is the realisation ­ not so long ago ­ of the importance of the financial market infrastructure, of which payment systems are an important part, for a safe and sound financial system. In fact, robust payment systems are widely considered to be a key requirement in maintaining and promoting financial stability. This was illustrated by the recent financial crisis where many things in the financial markets went wrong, but the payment systems ­ even at the worst moments when some of the markets froze ­ turned out to be resilient. The main reason that the financial markets managed to avoid serious problems at the level of the