Ion beam processing is a means of producing both novel materials and structures. The contributions in this volume strongly focus on this aspect and include many papers reporting on the modification of the electrical and structural properties of the target materials, both metals and semiconductors, as well as the synthesis of buried and surface compound layers. Many examples on the applications of high energy and high dose ion implantation are also given. All of the papers from Symposia C and D are presented in this single volume because the interests of many of the participants span both topics. Additionally many of the materials science aspects, including experimental methods, equipment and processing problems, diagnostic and analytical techniques are common to both symposia.