In a globalised economy, economic imbalances between the main areas have a global impact.The supervision of economic policies is a major issue for stability. The latter is achieved mainly through two levers: monetary and fiscal. In this book, we will focus on the monetary policies conducted by central banks, which are by nature responsible for the stability of the banking and financial system. The 2007-2008 crisis is a perfect example of instability. Shouldn't the evolution of economic conditions lead to a restructuring of the objectives of central banks and monetary policies?