Radicalization is the process of adopting an extremist value system combined with an expression of approval, support or use of violence and intimidation as a means of achieving changes in society, or encouraging others to do so. The ultimate and the most extreme stage of radicalization taken by an individual or a group are terrorist activities. Identification of sources of extremist threats is therefore an important tool to combat the phenomenon of radicalization, as well as its later phases, which include terrorist violence. To have a thorough knowledge of the threat scale and identify the most extremist groups, it is reasonable to determine economic, psychological, social, political and religious factors fostering the development of radicalization. The key element in this regard is the way an individual perceives his/her own person and the world around as well as his/her specific beliefs pertaining to the phenomenon of extremism. The danger of radicalization not only lies in the fact that it may be associated with violence or the threat of its use, but it may also be a causal factor of other forms of harmful effects on society.