Given the problems of the environment in relation to the ever-growing civi­ lization activities of man, it is not surprising that in recent years more and more related data have been collected, phenomena have been observed and concerns have been expressed. The ecological systems of man's environment react to the impact of these civilization activities. In fact, quite often these reactions occur as shocks and surprises. Acid rain and the related forest die backs are but one example. Ecological systems consist of many components and their dynamics is thus complex. The study of complexity is the underlying theme for work at KFA Jiilich. A major part of this work concerns the physics of condensed matter, including polymers, spin glasses, surfaces and layers. Another part relates to micro­ electronics in the submicrometre range in its relation to the design of vector and parallel computers. Supercomputing characterizes this search for the understanding of complexity further. But equally the work on the chemistry of the atmosphere, radio agronomy, biotechnology and research on information processing on the molecular level must also be mentioned. To make the picture complete, at KFA Jiilich work on reactor technology, fusion research and energy systems of course continues. These are complex systems too.