This chapter outlines the problem, research objectives, methods, groups of sources, and limitations (comparative method, correlational analysis, media and content analysis, and the use of historical/archival data). It introduces theories of “mixed-ideology” extremism and “terrorism of atmosphere” as fundamental frameworks for the research. The study adopts the lens of constructivism in international relations and security studies as the most suitable framework for understanding how political violence and extremism are shaped by narratives, identities, and social context.