Looking at the development of fa ade technology, after 60 years of curtain wall systems, 30 years of element-fa ade systems and ten years of experience with the integration of environmental services in double fa ades, it is clear that the peak of optimization has been reached. No further technical developments can be expected by continuing to apply extra layers for each additional technical function. By understanding fa ades (or envelopes) as part of an integral building, we can see that creating the future envelope has to be done on a 'network' basis: employing systems and methods of thinking that provide the possibility to develop different aspects simultaneously, and to combine them as required. The envelope has to be seen as a functional part of the entire building, serving a part of the demand by providing the necessary technologies and qualities. In this regard, we must withdraw from material and structure-orientated thinking and construction, instead developing the envelope as a hybrid system. Materials, technologies and production processes have to be integrated in the summation and combined into an all-encompassing result. Fa ades comprises various themes covering strategic, material and technological developments. Aspects such as function integration, networking of elements, new structures and materials as well as the addition of functions to existing structures are investigated and explained in 85 examples.