Learning technologies are becoming a common, and in many cases essential, component of the contemporary learning environment. As such, those who design, implement and control these encompassing technologies have emerged as major contributors to the success (or otherwise) of such systems. This article considers the power and responsibilities of learning technologists and the ways that they affect the teaching and learning environments around them. It does this by investigating, through semi-structured interview, the praxis of a learning technology group at the University of Edinburgh and relating this to professional issues for learning technologists in general. The article goes on to develop a typology of learning technology service provision based on the relationship between the learning technologist and the context in which their work is to be used. This is compared with interviews with practitioners, and a series of principles and recommendations is then developed. The thrust of these is that direct participation in the learning community is essential for learning technologists and that common codes of practice for learning technologists are required, both as a benchmark and as a framework by which professional practice can be measured and developed. (Contains 4 notes.)