Taking into account legal, societal, operational and democratic perspectives, this collection connects theoretical and practical perspectives to produce an interdisciplinary and multi-stakeholder study of how we might measure and understand the impact, legitimacy and effectiveness of EU counter-terrorism. Bringing together a select group of experts in the field, particular emphasis is placed on understanding the practical experience of implementing and assessing these measures gathered from and with end users, including law-makers, policy-makers, security services, industry partners and civil society.