This chapter introduces the central focus and conceptual framing of the book’s inquiry into the role, efficacy, and foundational assumptions of online strategic communications within the Preventing and Countering Violent Extremism (P/CVE) sector. It situates the discussion in the evolving digital environment, where counternarratives—messages and campaigns designed to derail pathways toward extremist violence—are disseminated to “vulnerable” and “at-risk” online audiences. The chapter posits that while these initiatives leverage sophisticated technological tools and data-driven approaches to influence audience behaviour, their underlying theoretical and conceptual bases often remain under-examined. Drawing on theories of radicalisation, deradicalisation, socialisation, and behaviour change, the chapter introduces a new evaluative framework, the “socialisation and reasoned action strategic communication” (SoRaSCo) model, to more rigorously test the strategic claims and asserted successes of P/CVE counternarratives. Ultimately, this chapter establishes the research parameters, theoretical underpinnings, and methodological approaches that guide the book’s subsequent empirical and analytical work.