Violent extremism and terrorism are relevant threats to peaceful coexistence across the world. Extremism prevention (sometimes also “counter violent extremism”) seeks to prevent radicalization processes in this direction and thus ultimately aims at preventing violent extremism and terrorism. This chapter provides an overview of extremism prevention. Based on a processual understanding of radicalization, we describe violent extremism and terrorism as possible, but not necessary, outcomes of a radicalization process. The occurrence of violent extremism and terrorism can be understood as the result of an interplay of risk and protective factors. These factors can be located at different levels (individual, extremist groups, society). The prevention of violent extremism starts at different stages of the radicalization process. Depending on the stage, it attempts to prevent radical worldviews (universal prevention), to avert a turn to extremism and violence (selective prevention) or to prevent (repeated) use of violence (indicated prevention), to promote a move away from extremist groups (distancing) or radical worldviews. We present some current prevention projects, especially from Germany, and illustrate the chapter with stories of people leaving right-wing extremism and Islamist extremism. Finally, we discuss the evaluation of extremism prevention.
