Money laundering and terrorist financing are serious crimes that affect not only those persons directly involved, but the economy as a whole. According to international standards, every bank has the obligation to know its customers and to report suspicious transactions. Although these obligations sound straightforward, they have proved challenging to implement. What information precisely has to be gathered? How should it be recorded? If and when does one have to file a suspicious transaction report? It is here that a supervisor can play a crucial role in helping supervised institutions; first, in understanding the full extent of the obligations of Customer Due Diligence and Suspicious Transaction Reports (STR) and, second, in ensuring that those obligations are not just words on paper but are applied in practice. Effective supervision is key to the success of a country's AML/CFT system. In this regard, field work in both developed and developing countries has shown an overall low compliance in the area of supervision of banks and other financial institutions; supervisory compliance is indeed generally lower than the average level of compliance with all Financial Action Task Force recommendations. As a result, by providing examples of good practices, this book aims to help countries better conform to international standards. In this regard, this handbook is specifically designed for bank supervisors.