How is criminal investigation organized? What are the main structures and systems? Which organizations are involved in such activity, and how is such work undertaken in areas such as high-volume crime and major crime inquiries? These are some of the core questions explored in Part 2 of the Handbook. The part opens with a look at international structures and transnational crime. As we noted in the Introduction to this book, the changing nature of communications and transport associated with the overall social transformation we have come to know as ‘globalization’ has had an impact on criminal opportunities as in all other areas of activity. Serious and organized crime involving the trafficking of goods (from drugs to weapons), the trade in people (from organizing immigration to trafficking for prostitution and slavery) to the enormous possibilities opened up by the electronic trade in money, are all evidence of the dramatic impact of globalization on crime. Criminal investigation has progressively reorganized itself in response, and Chris Lewis examines a number of the key structures such as the United Nations, Interpol and Europol, as well as some of the newer, more specific powers such as the European Arrest Warrant. He illustrates some of the continuing variation that exists in the investigation of organized crime across the EU, and argues that both national jurisdictions and transnational bodies have generally been slow to change their structures and to move their resources in response to the changing nature of the problems they have to confront.