ABSTRACT Boundaries in expertise may be natural borders between clearly different activities, but expertise changes over time and boundaries can get out of date. Boundaries can become barriers between people, if they are jealously guarded. Alternatively, boundaries can be a point at which we acknowledge that something has changed and must adapt to new circumstances. This paper looks at how boundaries have been created in design and engineering in the last two centuries, the ways in which they have affected our understanding of our work and possible ways to improve matters.