Engineering Students Understanding Mathematics (ESUM) is a developmental research project at a UK university. The motivating aim is that engineering students should develop a more conceptual understanding of mathematics through their participation in an innovation in teaching. A small research team has both studied and contributed to innovation, which included small group activity, a variety of forms of questioning, an assessed group project and use of the GeoGebra medium for exploring functions. Perspectives of community of practice and inquiry, and documentational genesis underpin the research approach. Issues and findings to date from the project are presented.