The Computer of future shall support us in all situations of our everyday life through continuous supply of valuable information. The realisation of this vision, which has first emerged at the end of the eighties, seems to take concrete shape, considering today's high performance computers and networks, as well as the advances in the sensor technology. This very topic and related fields have also been subject to enormous dedicated research (Ubiquitous Computing, Pervasive Computing, Context-aware Computing, Disappearing Computing, Ambient Intelligence, Smart Spaces, etc.).
The modern "everyday computing" requires a novel form of human-computer-interaction. Accordingly, the design of an appropriate interface between the human and the computer will be of eminent importance. The "disappearing" computer of future will be fully integrated in the physical spaces of our daily life, such that any explicit input-output via traditional interfaces will not be needed anymore. The leverage of space and objects of everyday life as an optimal interface is quite straight forward, since human beings deal with such objects fully naturally and with ease. Therefore, a considerable amount of multidisciplinary research focuses on studying the human behaviour in his various physical environments. In this work, I discuss different aspects of the above mentioned vision along with a number of applied technologies for its realisation, as well as few examples for the integration of the interactive technology in the physical space. Furthermore, I elucidate the issue of human perception of the physical space and its interplay with the human-computer-interaction.