This paper discusses the notion of a thing (Ding) in Heidegger. Its aim is to explain the systematic place of that notion in Heidegger’s thought in relation to his ontological discourse: as what is explained through different understandings of being, things allow for a simultaneous differentiation and discussion of the different epochs in the so-called history of being. Thus a henomenology of things and thingness serves as frame of reference for all explications of ‘what there is.’ If Heidegger is a realist, it is not because he attributes reality to all that is, but rather because all explanations of being refer back to how things are discovered as meaningful.