The research group led by Esther Barbé participated as a partner in the CHALLENGE project (The Changing Landscape of European Liberty and Security), funded by the European Commission (Sixth Framework Programme). Under the leadership of Sciences Po-Paris (Didier Bigo) and CEPS Brussels, CHALLENGE established a network of 21 institutions across Europe. The project analysed the concept of security in the EU’s external borders based on widespread concern about the illiberal practices in contemporary liberal regimes and the tension between freedom and security. The contribution of the group was reflected into 13 documents produced by the group itself or in co-authorship with other institutions collaborating in the project, as well as in a chapter of the collective book Europe’s 21st Century Challenge. Delivering Liberty (Routledge 2013).