The idea of the global extremism index reflects the need for international cooperation in combating dangerous manifestations of the ideology of political violence and hate speech. In conditions when the norms of national and international law guarantee the mass media access to a global audience, the ability to exercise freedom of speech in the interests of cultural exchange and sustainable development becomes of fundamental importance. The monograph, prepared by a team of specialists in the field of law and mass communications, examines the political and legal aspects of assessing the public danger of various manifestations of violent extremism.