Book excerpt: On September 10-13, 1990, the first international meeting on Microsystem Technologies takes place at the Berlin International Congress Center. Most of the traditional congresses deal with themes that become more and more specific, and only a small part of the scientific world is reflected. The Micro System Technologies is attempting to take the opposite direction: During the last two decades the development of microelectronics was characterized by a tremendous increase of complexity of integrated circuits. At the same time the fields of microoptics and micromechanics have been developed to an advanced state of the art by the application of thin film and semiconductor technologies. The trend of the future development is to increase the integration density by combining the microelectronic, microoptic, and micro mechanic aspects to new complex multifunctional systems, which are able to comprise sensors, actuators, analogue and digital circuits on the same chip or on multichip-modules. Microsystems will lead to extensions of the field of microelectronic applications with important technical alterations and can open new considerable markets. For the realization of economical solutions for microsystems a lot of interdisciplinary cooperation and know-how has to be developed. New materials for sensitive layers, substrates, conducting, semiconducting, or isolating thin films are the basis for the development of new technologies. The increasing complexity leads to increasing interaction among electrical and non-electrical quantities.