Now retired, so... Looking back to my career, I can see two periods: Mathematics Education (from 1974 to 1988), Technology Enhanced Learning (since 1988), with a non-empty intersection. An issue I am currently interested in, is that of understanding why it is so difficult to establish the knowledge base in the latter. I anticipate that this has both an epistemological and a social dimension. I have chosen to address this issue by promoting the adoption of an encyclopaedic approach. The first step is to gather the words we use and to make explicit the concepts to which they are related, to understand their variety, and identify the discrepancies in understanding them. The outcome will be a thesaurus and a dictionary. Given the importance of culture and epistemology in the Learning Research area we have to be prepared to face differences (even disagreement) due to the differences between our languages (what is often hidden by an unquestioned use of English by non-Anglospeaker) or even of our disciplines. The TEL dictionary initiative is an attempt to engage in this direction. Once the creation of a thesaurus and dictionary will have made significant progress, then the next step will be the creation of an encyclopaedia to describe and support the TEL knowledge base, very likely based on a wikipedia project. This project will be carried out involving communities in the context of the Stellar EC FP7 Network of Excellence (NoE) and the scientific association TELEARC ( the legacy association of the FP6 NoE Kaleidoscope). Specialties:technology enhanced learning, mathematics education, didactics of mathematics, mathematical proof, learner modelling