This handbook provides a theoretical and methodological exploration of the research on radicalisation and counter-radicalisation, one of the most influential concepts in Security Studies, International Relations, and Peace and Conflict Studies.

Joel Busher is Professor of Political Sociology at the Institute for Peace and Security, Coventry University. He is co-editor of Researching the Far Right: Theory, Method and Practice (Routledge, 2021) and author of The Making of Anti-Muslim Protest (Routledge, 2016), which was awarded the British Sociological Association's Philip Abrams Memorial Prize.

Leena Malkki is Director of the Centre for European Studies at the University of Helsinki. She is the chair of the ECPR Standing Group on Political Violence and a member of the editorial board of Terrorism and Political Violence.

Sarah Marsden is Senior Lecturer in the School of International Relations at the University of St. Andrews. She is the author of Reintegrating Extremists: Deradicalisation and Disengagement.

1. 1. Introduction Part I: The History of Research on Radicalisation 2. Before 'radicalisation': Explaining individual involvement in terrorism before the popularisation of the radicalisation concept 3. 'Radicalisation' and 'countering radicalisation': The emergence and expansion of a contentious concept 4. Analysing 'radicalisation' in historical cases Part II: Analytical Approaches to Radicalisation 5. The role of ideology in radicalisation 6. Identity and Extremism: Sorting out the causal pathways to radicalisation and violent self-sacrifice 7. Social movement theory and research on radicalisation 8. Criminological perspectives on extremist radicalisation and terrorist acts 9. Insights from the study of new religious movements into the process of radicalisation 10. The pen and the sword: Cognition, emotion, communication, and violent radicalisation 11. Gender perspectives on radicalisation 12. Radicalisation and psychopathology 13. Belonging is just a click away: Extremism, radicalization, and the role of online communities 14. Radicalisation of 'lone actors' 15. Radicalisation of 'foreign fighters' Part III: Countering Radicalisation: Key Debates 16. Countering violence or ideas? The politics of counter-radicalisation 17. Responding to radicalisation with different ideological roots: How similar is the 'problem'? How similar are the 'solutions'? 18. Who should be involved with counter radicalisation policy and practice? 19. Working with communities to counter radicalisation 20. The role of research and researchers in counter-radicalisation policy and practice 21. How can we meaningfully evaluate the effects and effectiveness of programmes to prevent or counter radicalisation? 22. Re-colonizing the field of evaluation of prevention of violent radicalisation: A critical, cross-regional perspective Part IV: Countering Radicalisation: Strategies and Challenges 23. Rethinking CVE and public health prevention: Towards health promotion 24. Multi-agency approaches to countering radicalisation 25. Naturalisation through mainstreaming: counter-terrorism and counter-radicalisation in UN and EU discourse 26. Countering radicalisation while expanding the criminal law 27. Responding to radicalisation through education 28. Counter narratives and strategic communications, offline and online 29. Deradicalisation and disengagement: Lessons from the Indonesian experience 30. Interventions with 'at risk' individuals 31. How can general violence risk assessment and management inform that of violent extremist risk? 32. Content moderation: Social media and countering online radicalisation 33. Radicalisation, counter-radicalisation and governance in fragile states 34. Local contours and global discourses in countering violent radicalization and extremism: A perspective from the Global South