This collection of papers examines a variety of areas and issues related to, or raised by, the EU Internal Security Strategy. It covers such matters as critical infrastructure protection and environmental crime, from a range of disciplinary perspectives, including law, geography and politics.The EU Internal Security Strategy is becoming increasingly complex as it develops over time, as it has to operate against the background of growing diversity in law enforcement systems across EU member states. It is clear that the EU Internal Security Strategy is, and will continue to be for a long time, a work in progress, not only in its aim to address traditional transnational security threats, but also in reacting to emerging concerns, either in new crime areas or issues arising from the implementation of earlier phases of the strategy. This will be a subject matter for many academic discipline areas for some time to come.