In this paper, we argue how a documentation-centred approach to systems design and development could provide the different roles involved in this activity with a common ground. A large heterogeneous development team can be seen as a Community of Interest, consisting of individuals brought together from different Communities of Practice. Each group brings to the CoI not only their own skills and experience but also their own values, mental models, working practices, and communication styles. Re-shaping documentation into a boundary object offers a solution to the dual problems of (1) heterogeneous mental models within a software development team and (2) the user support role being peripheral to the team. Documentation that evolves dynamically, changing shape as the development process proceeds, can support communication both internally (between members of a software development team) and externally (between developers and end users).