This Inaugural Special Issue of Studies in Technology Enhanced Learning has a particular focus on ‘theory’—a contentious matter. Occasionally disparaged as obscure, or alienating, it seems fair to say that theory has never been so deeply embedded in Technology Enhanced Learning (TEL) research as it has become in many other areas of scholarship. One reason is that TEL is often conceived as a ‘practical’ field, with ‘theory’ negatively counterposed against other priorities: methodological innovation, ‘evidence’, ‘best practice’, or, more recently, imperatives towards being ‘data driven’. Furthermore, the use of theory can often be a stumbling block for many novice researchers: even those inclined towards ambition in their use of theory can struggle in getting to grips with the attendant vocabularies, or when actually using particular theories in their own research. Many may come to wonder whether doing so is really worth the effort.

The impetus for the present issue is a contention that ‘theory’ really matters for TEL. That contention is widely shared by members of the Centre for Technology Enhanced Learning , a research centre at Lancaster University, UK, which, while part of the Department of Educational Research, has members drawn from a variety of disciplines. Indeed, the initial idea for the issue grew out of a longstanding sequence of discussions within the Centre—which the two present authors, at the time of writing, jointly direct—which have expressed a desire to emphasise the importance of ‘theory’ to others. One earlier idea, for example, had been for the Centre to write a “report” on theory in TEL research. The current Special Issue was taken up, instead, as we came to realise that the idea of collectively writing about ‘theory’ might dovetail with the idea of launching an open-access journal, and that a Special Issue might allow for a more multi-vocal consideration of the subject matter.