This volume explores political polarisation in contemporary democracies with a special focus on Greece from 2010 to 2023. It investigates how polarisation functions not merely as a divergence of opinion but as a multi-level and emotionally charged process that influences public discourse, media narratives, and political identities. The core conceptual framework distinguishes between issue-based and affective polarisation, and proposes a Dynamic Model of Polarisation along with a Threat Model. These models trace how elites and grassroots actors mutually reinforce divisions through rhetoric and identity framing. Greece serves as a case study where successive crises—economic, migration, and the Prespes Agreement—have triggered a spiral of polarisation across political, media, and social arenas. The volume employs an interdisciplinary methodology combining quantitative and qualitative content analysis, sentiment analysis, and dictionary-based techniques. Through its six empirical chapters, the volume reveals how political polarisation becomes institutionalised, how it mutates through new issues and identities, and how it ultimately reshapes democratic participation and cohesion.