Twelve years ago, the Federal Institute for Geosciences and Natural Resources (BGR) held the first International Raw Materials Symposium. At that time the raw materials markets were going through a crisis. Political influence and the strategies of cartels governed the market much more than the law of supply and demand. The public was deeply alarmed by the question: How long will the reserves of raw materials last? How different is the scene today! Today, geoscientists have to warn the public not to fall into the opposite extreme, into carelessness. Today, as before, raw materials are endowments of the earth, they are non-renewable and they are limited. We must not cease in our effort to conserve raw materials, to recycle them and find substitutes, even if the markets today are balanced and prices are low. In previous symposia the following topics were discussed: The importance of the Geosciences for the Supply of Mineral Raw Materials; The Mineral Resources Potential of the Earth; New Paths to Mineral Exploration; Geo-Resources and Environment. The subject of the fifth Symposium relates to technological developments. From the beginning, raw materials and technology have stimulated each other. Today, we are experiencing breathtaking developments in information technology and in the search for new materials. They present new goals and new problems for geoscientists. This symposium will discuss them. Internationally recognized experts have offered to contribute to the symposium. My special thanks are due to all of them. It is not easy to communicate across barriers. Engineers and scientists often use different languages, think in different categories. To be able to understand each other they have to think and do talk in simple terms. This can be quite difficult. The participants of this symposium come from many fields of science and engineering, even from politics. It is my sincere wish that each one of them will receive stimulating information and new ideas. It may well be that geologists have to learn that the required new raw materials cannot be sought in the conservative way, that they are not required in large quantities, and that more often than not they are obtained as by-products. Technologies have to be developed to separate these by-products from the main mineral components of a deposit. Special quality standards for the new raw materials have to be complied with. A whole range of new challenges emerges and can be tackled only in a multidisciplinary approach comprising the combined actions of geoscientists, engineers and technicians. I am confident that this symposium will contribute to the advance of new technologies and will bring geoscientists and engineers closer together.