This text presents a comprehensive treatment of the most important topics in monetary economics, focusing on the primary models monetary economists have employed to address topics in theory and policy. It covers the basic theoretical approaches, shows how to do simulation work with the models, and discusses the full range of frictions that economists have studied to understand the impacts of monetary policy. Among the topics presented are money-in-the-utility function, :ash-in-advance, and search models of money; informational, portfolio, and nominal rigidities; tredit frictions; the open economy; and issues of monetary policy, including discretion and commitment, policy analysis in new Keynesian models, and monetary operating procedures. This third edition of Walsh’s by-now classic on monetary economics represents a major revision and expansion of the previous edition, incorporating new developments in theory, modeling practice, and policy insights. This book is a pleasure to read and study with, thanks to the right balance of insight, rigor, and accessibility.