The concept of 'radicalization' is now used to account for all forms of violent and non-violent political Islam. Used widely within the security services and picked up by academia, the term was initially coined by the General Intelligence and Security Service of the Netherlands (AIVD) after the 9/11 and Pentagon attacks, an origin that is rarely recognised.

This book comprises contributions from leading scholars in the field of critical security studies to trace the introduction, adoption and dissemination of 'radicalization' as a concept. It is the first book to offer a critical analysis and history of the term as an 'empty signifier', that is, a word that might not necessarily refer to something existing in the real world. The diverse contributions consider how the term has circulated since its emergence in the Netherlands and Belgium, its appearance in academia, its existence among the people categorized as 'radicals' and its impact on relationships of trust between public officials and their clients. Building on the traditions of critical security studies and critical studies on terrorism, the book reaffirms the importance of a reflective approach to counter-radicalization discourse and policies. It will be essential reading for scholars of security studies, political anthropology, the study of Islam in the west and European studies.

Nadia Fadil is Associate Professor in Anthropology at the Interculturalism, Migration and Minorities Research Centre (IMMRC) at Catholic University of Leuven (KU Leuven) in Belgium. She has published extensively in academic journals, including HAU, Ethnicities, Identities, Social Anthropology, Ethnic and Racial Studies and the Feminist Review as well as in edited volumes.

Francesco Ragazzi is Lecturer in International Relations at Leiden University and Associated Scholar at the Centre D'Etude sur les Conflits, Liberté Security (CCLS). He has published widely in peer-reviewed journals including International Political Sociology, Security Dialogue and Political Geography. He has been consulted as an expert on security by the European Parliament, the Council of Europe and the French Senate.

Martijn de Koning teaches at the Department of Islamic Studies at Radboud University Nijmegen in the Netherlands. He is also a post-doctoral researcher at the Department of Anthropology at the University of Amsterdam. He has published in the Journal of Muslims in Europe, Anthropology Today and Contemporary Islam.