In recent years ‘theory’ has been much debated in journals devoted to, among other areas of study, literary and historical research. Depending on your outlook, theory is seen either as of positive value to an advance in the understanding of a particular problem or set of problems; or as an irritating irrelevance, indeed a hindrance, to the progress of good research work. Many ‘theorists’, certainly, have gone to the extreme of dismissing empirical historical research as itself irrelevant, founded upon epistemologically indefensible premises and hence misleading if not worthless. While such views are hardly designed to encourage serious engagement with theoretical issues, it is the polarisation of positions of which they are symptoms that I would like to look at in what follows. This article is an overview that will deal in basics. I want to look at the role theoretical debate has taken in historiography generally, and in the area of Byzantine and Modern Greek Studies in particular, and the attitudes of its practitioners.