The new challenges that international terrorism presents to security constitute the latest of the revolutions in the nature of armed conflict that the world experiences approximately every fifty years. Like the ones before it, the current revolution has been driven by a multiplicity of factors. It is mainly characterised by the proliferation of technology, the growing gap between rich and poor countries and the information revolution. The nature of the new threats calls for responses that are non-military. The nature of military forces also has to change to combat these threats. The implications of these changes for NATO and the EU are analysed. Various actors need to form a ‘security community’ in order to effectively combat these threats.