The chapter provides a brief historiography of critical heritage studies as a distinct research discipline interested in heritage evaluation as a cultural practice with political consequences, through which we might understand more about the structures which shape and are shaped by socio-political contexts. The chapter considers the role of theory in defining what critical heritage is, as a representative practice, a discourse, or as an affective, sensory, and embodied encounter between people and things. In introducing the concept of communities of practice, originating in education and participation theory, the chapter complicates notions of heritage expertise, professionalism, and the non-expert. A case study of London bus enthusiasm is presented to explore how everyday cultural practices are conferred with heritage significance. This occurs during ongoing encounters with authorised heritage forms through which expertise is expressed at the boundaries between different actors, based not on who they are but rather on what they do.