Our work in the field of mixed reality has been concerned with the development of the mixed reality boundary approach. In contrast to other approaches that focus on superimposing the virtual and the physical environment, the spaces on either side of the boundary are adjacent but remain distinct. In this position statement we describe the development of mixed reality boundaries, including the basic idea, the properties that can be associated with them and demonstrators. We also discuss our latest work on a particular type of boundary that establishes the illusion that virtual and physical worlds are joined together and that users can physically cross from one to the other. Keywords Mixed Reality Boundaries, Virtual Environments, Telepresence, Augmented Reality MIXED REALITY BOUNDARY APPROACH Our work in mixed reality has been focused on developing mixed reality boundaries. These represent a specific approach to mixed reality that involves creating transparent windows between physical a...