The BookCrossborder threats have increased the importance of internal and external security for the EU Member States. In this respect, the 2020 EU Security Union Strategy provides a coherent regulatory framework for numerous concepts, strategies and action plans in the field of EU security measures concerning, e.g.Critical infrastructure and network information systemsCounterterrorismInstitutional intelligence cooperationThese and numerous other security issues are discussed in the book, providing clarification and insights into the extent and limits of European security cooperation and the degree to which Member States remain solely responsible for their own national security, especially in light of recent ECJ case law.The Advantages at a GlanceComprehensive discussionRelevance to the current geo-political situationTeam of expert authorsThe Target GroupFor practitioners and experts from academia, EU and national institutions, and security organisations.