The knowledge gathered through research in environmental psychology is not optimally used by designers and other people working in applied settings such as politicians and civil servants. In this paper a number of causes and possible improvements of this situation will be discussed. Two aspects are highlighted in particular: the structure and the presentation of information. A recent development to present knowledge from environmental psychology is the use of computerized Information systems or expert systems. Limitations and possibilities of expert systems in general and for environmental psychology in particular will be discussed. The issue is Illustrated with parts of an expert system on the design of children's play environments using the pattern language as a structure to present information efficiently and attractively to designers.