Following 9/11 and the terrorist attacks in western Europe over the past two decades, research on religiously inspired or attributed violent radicalisation has grown into a field of study that has developed a broad and sophisticated range of explanations, theories, and categorisations about violent attacks that are either claimed by groups linked to Islamist ideologies or individuals inspired by them. Within this field, measuring the impact of programmes designed to prevent and counter violent extremism (P/CVE) has attracted increasing interest. While significant research in this field exists in countries that have suffered the most symbolic and mediatised attacks, there is less research being conducted on countries hosting significant Muslim communities of recent arrival such as Italy, Greece, and Spain where there have either been no or very few religiously inspired violent attacks (Italy and Greece) or where such attacks have not triggered the same securitised response (Spain) as elsewhere. Bringing together the three country studies presented in this book—as well as our desk research and contribution to those—this chapter introduces the rationale for this southern European comparative analysis, presents our methodology, and outlines the contents of the chapters that follow.