While the development towards a digital library is moving on since the last decades there are intense building activities in the field of libraries at the same time. It is postulated that there are four causes for this development: 1. The need for access to education and science grows faster than the possibilities for usage of library services via home computing. 2. The increasing costs for media acquisition which lead to decreasing total acquisition numbers are compensated by more visible investments into library buildings. 3. An increasing number of people is constraint to solve their educative and scientific problems collaborating in teams 4. The state of modern librarianship can be demonstrated more easily by means of showy library buildings than by means of sophisticated knowledge management systems. In result there is a higher number of visitors after new openings. How this number depicts the actual economic, educational or scientific impact of libraries, has to be shown in regard to the outcomes of the work within the “digital library”. Therefore there is a urgent need for library science to deal more intensivly with the analysis of the usage of these new and additional buildings emphasizing their capableness. As trend analysis show, the library of the future will and shall be an optimal networked and distributed space for working, learning and communication. Hence the criteria for the appraisal of adequacy of these new buildings can be gained.