The key aim of monetary policy for most central banks is to keep inflation low and steady. However in a market-oriented economy, central banks cannot control inflation directly. They have to use instruments such as interest rates, the effects of which on the economy are uncertain. And they have to rely on incomplete information about the economy and its prospects. Some central banks use money growth or the exchange rate as intermediate targets to guide policy decisions. Others take a more eclectic approach and consider a range of factors. Monetary policy has occupied much time of the world’s most distinguished economists over the years. This Handbook provides an introductory overview to the subject. Following the introduction in Section 1, Section 2 describes the main costs of inflation. The next section provides an overview of the various routes by which monetary policy transmits through the economy. And Section 4 describes the alternative targets which central banks can use to guide policy. Some conclusions are provided in Section 5. The purpose of this Handbook is to assist monetary policy practitioners - those in central banks and governments who are advising and taking decisions on monetary policy. Those new to the subject may, it is hoped, find this a useful starting point for further reading and research. This handbook is also available in Russian and Spanish.