This thesis aims to define and evaluate the role and design of digital information systems in museums. In order to do this, the study addresses the following topic areas: the tasks of museums as institutions for the public, the conception of digital information systems and the interdependencies between content structure and graphic design, illustrated by a practical example. Experiences made by European museums in digital media projects have served as a starting point. The report investigates the role of digital media as information mediators by looking at Human Computer Interaction and compares different models and structures used for computer-based information provision. In a second part, the thesis outlines the practical use of several theoretical aspects mentioned by presenting the design and evaluation approach carried out during the conception of the medien.matrix, a digital visitor information system at the Vienna Museum of Technology. The most significant results of the investigation can be summarized as follows: Museums primarily have an educational task to fulfill. Virtual information spaces cannot replace real exhibitions but can rather complement them, the only exception being virtual (online) museums, which lack physical objects. A graphic design can only provide didactic support if the content basis is clearly structured. The thesis concludes with some thoughts about the resources and factors which are vital for a future knowledge society.