This book (which is Stephan Sauer`s Ph.D. thesis at the University of Munich) applies a wide range of economic methodologies to the analysis of monetary policy. The first chapter introduces current challenges for central banking and summarises the results. Chapter 2 looks at optimal monetary policy in the modern micro-founded New Keynesian macroeconomic model, while chapter 3 offers an empirical investigation of monetary policy in the euro area. The final chapter 4 combines a microeconomic model of liquidity shocks on an asset market that includes features of market microstructure theory with a model of the goods market inspired by nominal rigidities as common in macroeconomic models. All three chapters are connected by the prominent role of different rules and the objective to develop and apply frameworks for the analysis of monetary policy from a theoretical and empirical perspective. The book aims at researchers and economists interested in monetary policy at academic and research institutions as well as central banks.