It is a pleasure to write a few words as an introduction to the proceedings of the 1980 NATO ASI on "Physical Processes in Laser­ Naterial Interaction." This ASI is the ninth course of a series devoted to lasers and their applications, held under the responsibility of the Quantum Electronics Division of the European Physical Society, and for this reason known as the "Europhysics School of Quantum Electronics." Since 1971 the School has been operating with the joint direc­ tion of myself as representative of the academic research, and Dr. D. Roess (formerly with Siemens AEG, Munich, and now with Sick, Optik und Electronik, GmbH, Munich) for the industrial applications. Indeed the aim of the School is to alternate fundamental and applied frontier topics in the area of quantum electronics and modern optics, in order to introduce young research people from universities and industrial R&D laboratories to the new aspects of research opened by the laser.