Most crime is committed for the money that is generated by it and the power that comes from having access to that purchasing power. Dirty money allows criminals to live lavish lifestyles and reinvest in further, oftentimes more serious, criminality. However, the money links its possessor to the crime that generated it, and adverse law enforcement attention is likely to follow. What is required from the criminal perspective is a process to obscure those links. That process is money laundering, and its regulation is anti-money laundering (AML). This chapter explores the development, nature, effect, and scale of money laundering. It then looks at the three-tiered response—international, supranational, and national—to prevent and detect money laundering. There is then a discussion of major plans by the European Union (EU) to revamp the current AML system over the coming decade. The chapter then outlines a model of Ireland’s AML system, which will be used throughout the remainder of the book. This model can be reused, with minor modifications, to describe any AML system that is based on the United Nations (UN) and the Financial Action Task Force (FATF) specifications. The chapter concludes by briefly discussing the major issues of concern around the current global AML system.