Shortly after the establishment of the Brown Boveri Research Center in 1967, plans were developed to organize a series of Brown Boveri Scientific Symposia, each hav­ ing a different topic, to be held every other year in Baden. We choose the subject for a symposium with the following requirements in mind: It should characterize a part of a scientific discipline; in other words it should concern an area of scholarly study and research. It should be of current interest in the sense that important results have recent­ ly been obtained and considerable research is under \\dY in the world's scientific community. It should bear some relation to the scientific and technological activity of the Company. These symposia are intimately related to one of the very basic concepts which have governed the work of many modern manufacturing companies: close coupling be­ tween science and engineering. It is to this coupling that we owe the technical stan­ dard of our products, and it is this coupling which we hope to be furthered by our symposia.