This book traces the history of the EU competence, EU policy discourse and EU legislation in the field of criminalisation from Maastricht until the present day. It asks ’Why EU Criminal Law?’ looking at what rationales the Treaty, policy document and legislation put forth when deciding whether a certain behaviour should be a criminal offence. To interpret the EU approach to criminalisation, it relies on both modern and post-modern theoretical frameworks on the legitimacy of criminal law, read jointly with the theories on the functions of EU harmonisation of national law. The book...