The communities in the Federal Republic of Germany are confronted with continually changing environmental conditions, which necessitate a constant checking of their attitudes and a systematic, purposive and long-range-efficient adjustment work. The problem is how, by using scientific planning methods, to make such adjustment processes more effective, how to rationalise, systematise, and organize them. Within modern planning technology the community has to be viewed as a system which is an over-dimensional network of cooperating elements and processes operating in a highly complex and stochastic way. It is embedded in systems of a higher order in which not only things (lots, buildings, machines, streets, etc.) but also people play a decisive role. In order to supply a rational planning calculus for such a system it has to analysed first, not only with regard to its IS-condition but also with regard to its future developments.