The first chapter constructs the book’s conceptual foundations by taking three steps. Firstly, it critically reviews the dominant model of preventing and controlling violent radicalisation and extremism. This approach is encapsulated in the Risk Need Responsivity model of rehabilitation and reducing recidivism. The book argues that this model is failing at practical, policy, political, and financial levels. This critique is not meant to be dismissive, but constructive in helping the development of alternatives. The chapter then attempts to make some conceptual agreements around key terms so that there is consistency in going forward. Restorative justice, positive criminology, and positive psychology, the three axes around which the book presents its arguments, are outlined, while its central concern of violence, including radical violence and extremism leading to terrorism, is presented. These conceptual agreements are not meant to be read as absolutes but used within the context of this book’s objectives. The chapter concludes by presenting the key push and pull factors that have been recorded in the extant literature as drivers of violent radicalisation and extremism. The chapter argues that this deficit approach is false. An important conclusion resulting from this chapter is that it is impossible to understand, let alone prevent, terrorism, violent radicalisation, and extremism if we do not approach them as the study subjects of our complex human behaviour.