Money laundering is criminalised virtually all around the world and has been a law enforcement priority since the early 1990s. The international nature of money laundering, combined with estimations on the scope and the distorting effects it may bring about, make it a grave danger to national and international financial markets. At the same time monehy laundering is considred to be a danger to society due to its strong interaction with organised drugs and white-collar crime. Over the years a 'twin-track approach'has been developed, aiming at the prevention of money laundering on the one hand, and punishing the money launderers on the other. This book analyses the effectiveness of the anti-money laundering supervision of banks, real estate agents and accountants in the Netherlands, Spain, Sweden and the United Kingdom. It thoroughly analyses the legislation, the institutional settings and competences of anti-money laundering supervisors, as well as the application of these competences in practice. Based on this analysis, a number of recommendations for the EU legislators and the national legislators are formulated in order to strengthen and increase the effectiveness of anti-money laundering supervision.