Radicalisation. A marginal phenomenon or a mirror to society ?

A decade and a half after the introduction of the concept of radicalisation in the toolkit of counterterrorism, radicalisation remains as fraught with conceptual confusion and divergent policy prescripts as at the beginning. The same questions as in 2004 are still being raised today. What exactly do we understand by radicalisation ? What are its key drivers ? How to articulate the link between radical thought and radical action and how does religion relate to it ?