Conflicts of Criminal Matters in the European Union, Volume 1: National Reports and Comparative Analysis; Criminal Law and Policy in the European Union; Tallinn Manual on the International Law Applicable to Cyber Warfare

The field of EU criminal law is now distinguishable from its father-field of international criminal law (although I accept that some EU criminal lawyers may in fact dispute the legitimacy of this lineage). In fact, one can certainly claim not only are they distinct but that the sources and scope of EU criminal law is even alien, to a large degree, from its more global counterpart. No doubt, whereas international criminal law developed chiefly through custom (e.g. in the case of piracy jure gentium and crimes against humanity) and treaty law (e.g. in the case of war crimes, grave breaches and transnational crimes such as drug trafficking and organised crime), EU law cannot be said to exist outside the primary EU (or EC) legislation granting relevant competences to EU institutions and member states. Of course, this is just one way of looking at the issue at hand because ultimately the origin of the substantive and procedural criminal law of the EU is in domestic legal systems and international or transnational law.