The purpose of this report is to map, conceptually and empirically, the diverse elements that constitute rightwing extremism. The aim is to offer readers a guide to this complexity and an appreciation for the numerous ideas, actors, and outcomes associated with RWE. The report is divided into two parts. The first focuses on the conceptual issues associated with RWE while the second explores how this complexity plays out in practice by examining various ways in which RWE has framed and reacted to Islam. This case study was selected as it illustrates the intricacies of varied and evolving RWE responses and because Islam and Muslims are often a major target of RWE violence and hostility.