In the introduction, we noted converging trends of political and religious extremism and associated violence, and the increasing role of the internet and World Wide Web in ordering both individual lives and societies. While this convergence has found its most dramatic expression in the study of militant Islamism online, we also noted a need to ensure that other narratives and ideologies were addressed by scholarship. In this volume, we invited scholars to submit work that dealt online extremism not related to militant Islamism. The response to the request was diverse. Perhaps predictably, as a widely acknowledged growing terrorist threat in many countries, the extreme right makes a strong showing, with several of the chapters choosing to focus on how the extreme right has adopted the World Wide Web. These include Jackson’s work in the field of ‘web history’ of the UK extreme right. It has also included contemporary analysis of the extreme right on social media, both through Facebook, in the chapter submitted by Scrivens and Amarasingam, and Twitter, in the chapter by Allchorn. Lee’s analysis of the use of memes by the extreme right is less tied to any one specific platform but still centres on the use on the extreme right and web technologies. The focus on the extreme right reflects both the growing pre-occupation with the apparent rise in popularity, or at least notoriety, of extreme right ideas online, and several recent incidents inspired by the extreme right including attacks in the UK by Darren Osbourne and Thomas Mair and the plots by figures including Jack Renshaw, and US attacks by figures such as James Fields and Dylan Roof. Most recently has been the wave of concern about the extreme right touched off by the terrorist murder of 51 people in Christchurch, New Zealand, by an Australian supporter of the extreme right.