Stuart Sim in his chapter offers a review of four texts that have made important contributions to critical theory since the 1970s. Each text engages critically with what might be termed classical Marxism and further, each text seeks to re-think classical Marxist ideas so as to assess their contemporary value. As a result, Sim’s analyses show that while the directions and outcomes of each text might differ somewhat, there is a conceptual thread that ties each text together and then in turn, connects each text to the signifier ‘post-Marxism’. This conceptual thread presented in the conclusion is relativism. Certainly, this conclusion has been important for critical theory because it has set a limit on the ability of classical Marxism to take a hegemonic position in the field. But there is also not a lot that is necessarily controversial about this conclusion, and certainly in the context of these texts. Notwithstanding the importance of exposing relativism as an important limit in the development of critical theory this chapter makes another important but far more controversial contribution to this collection on Laclau and Mouffe and post-Marxism, which in turn can be organised around two issues. The first issue is the exposure of the complexity inherent to the meaning of the signifier: post-Marxism and, for this reviewer at least, this is connected to Sim’s position that its signified can be and/or is marked, somewhat antagonistically, by the inclusion of a rejection of or (anti)-Marxism. The second is organised around the contemporary ‘nature’ of post-Marxism and in particular the theoretical engagement with relativism via postmodernism and poststructuralism and further, this offers an opportunity to consider how we ‘should’ understand this engagement. Sim is correct in making the point very early in the discussion that Marxism has ‘always had its share of internal critics’. In other words, critical evaluations and revisions have very often come from within the Marxist camp itself and these have been accepted primarily because certain foundational principles were considered not to be put in jeopardy. For example, the idea that the concepts of hegemony or even overdetermination could be read as, or might support, a post-Marxist project would and has certainly elicited strident challenge from some quarters.