This volume is based on lectures and contributed papers presented at the Eighth Course of the International School of Materials Science and Tech nology that was held in Erice, Sicily, Italy at the Ettore Majorana Centre for Scientific Culture during the period 1-13 July 1985. The subject of the course was "Electromagnetic Surface Excitations". Forty lectures were given by eleven distinguished scientists and engineers from France, Italy, the United Kingdom, and the United States. In addition to the lectur ers, approximately fifty participants representing eleven different countries throughout the world t. ook part in the course. Short contributed papers were presented by seventeen participants on the results of their own re search. The subject of the Course is of great importance for both pure science and for practical applications such as telecommunications. A technolog ical revolution is occurring in which the transmission of information by means of electrical currents travelling in copper wires is being replaced by transmission by means of light travelling in objects known as optical wave guides. The manipulation and processing of the light signals prior and subsequent to transmission through the wave guide has resulted in a technology often referred to as integrated optics. Important to the opera tion of integrated optics devices is the behavior of electromagnetic waves near surfaces and interfaces. One of the goals of the course was to further the dialogue between engineers and physicists in common areas of interest related to the propagation of electromagnetic waves along surfaces.