This book examines the use of communications efforts in preventing and challenging extremist narratives online. These efforts are part of the expansive and well-resourced sector of preventing and countering violent extremism (P/CVE). They leverage technology tools (algorithms, direct messaging, and audience targeting) to communicate counter-extremist messaging across various digital platforms. The research and discussion focus on the role of strategic communications in deradicalizing and changing the behavioral features of ‘vulnerable’ and ‘at-risk’ audiences susceptible to extremist messaging. This approach views radicalization pathways toward violence as a key issue to tackle within online P/CVE communication efforts. This book investigates this problem and seeks to understand and assess the role, efficacy, and implications of such efforts within the broader counter-terrorism (CT) landscape, using UK counter-terrorism efforts (via the Prevent Strategy) as its primary contextual source. This analysis applies the theory of socialization, referred to in this study as ‘socialization and reasoned action strategic communication’ (SoRaSCo). The authors identify strategic communications deficiencies and offer insights for developing a roadmap for strategic communications in P/CVE in the UK and globally. Drawing on extensive research, the book provides crucial insights for policymakers, researchers, and the public interested in new trends in P/CVE, counter-terrorism, strategic communications, and policing interventions.