This thesis is a contribution to design-led research and addresses a readership in the fields of architecture as well as in media and communications. In juxtaposing the tools of the designer (e.g. drafting, prototyping, visual/textual/spatial forms of montage) with those of architectural theory, this thesis seeks to extend the disciplinary boundaries of architecture by observing its assimilation of other media practices. Its primary contribution is to architectural design and theory, and its aims are twofold: Firstly, this thesis applies the concepts of virtual and mediated space to architecture, proposing an extended architectural practice that assimilates the concept of remote presence. Through realized design examples as well as through the history and theory of related concepts, the thesis explores what designing mediated spaces and designing for presence entails for the practicing architect. As a fusion of architecture and media technology, video-mediated spaces facilitate collaborative practices across spatial extensions while simultaneously fostering novel and environmentally sustainable modes of communication. The impact of presence design on workplace design is examined. As an extended practice also calls for an extended discourse, a preliminary conceptual toolbox is proposed. Concepts are adapted from related visual practices and tested on design prototypes, which arise from the author’s extensive experience in designing work and learning spaces. Secondly, this thesis outlines presence design as a transdisciplinary aesthetic practice and discusses the potential contribution of architects to a currently heterogeneous research field, which spans media space research, cognitive science, (tele)presence research, interaction design, ubiquitous computing, second-order cybernetics, and computer-supported collaborative work. In spite of such diversity, design and artistic practices are insufficiently represented in the field. This thesis argues that presence research and its discourse is characterised by sharp disciplinary boundaries and thereby identifies a conceptual gap: presence research typically fails to integrate aesthetic concepts that can be drawn from architecture and related visual practices. It is an important purpose of this thesis to synthesize such concepts into a coherent discourse. Finally, the thesis argues that remote presence through the proposed synthesis of architectural and technical design creates a significantly expanded potential for knowledge sharing across time and space, with potential to expand the practice and theory of architecture itself. The author’s design-led research shows that mediated spaces can provide sufficient audiovisual information about the remote space(s) and other person(s), allowing the subtleties of nonverbal communication to inform the interaction. Further, in designing for presence, certain spatial features have an effect on the user’s ability to experience a mediated spatial extension, which in turn, facilitates mediated presence. These spatial features play an important role in the process through which trust is negotiated, and hence has an impact on knowledge sharing. Mediated presence cannot be ensured by design, but by acknowledging the role of spatial design in mediated spaces, the presence designer can monitor and, in effect, seek to reduce the ‘friction’ that otherwise may inhibit the experience of mediated presence. The notion of ‘friction’ is borrowed from a context of knowledge sharing in collaborative work practices. My expanded use of the term ‘design friction’ is used to identify spatial design features which, unaddressed, may be said to impose friction and thus inhibit and impact negatively on the experience of presence. A conceptual tool-box for presence design is proposed, consisting of the following design concepts: mediated gaze, spatial montage, active spectatorship, mutual gaze, shared mediated space, offscreen space, lateral and peripheral awareness, framing and transparency. With their origins in related visual practices these emerge from the evolution of the concept of presence across a range of visual cultures, illuminating the centrality of presence design in design practice, be it in the construction of virtual pictorial space in Renaissance art or the generative design experiments of prototypical presence designers, such as Cedric Price, Gordon Pask and numerous researchers at MIT Media Lab, Stanford Institute and Xerox PARC. / QC 20100909