A State is all the stronger as it can retain what lives and acts against him. Paul Valéry, Mauvais thoughts and others, Missing the foreword of a Quaderni figure dedicated to the place of digital technologies in radicalisations by citing Paul Vale Éry on the strength of the State, may seem to be independent if this kind of commitment is placed exclusively in the light of the sociology of collective action and forms of social socialisation. The overall tone of this dossier is to combine the achievements of these approaches by capturing from a cultural perspective radicalisation understood as a cognitive and political process.