5) To what extent do events occurring during regeneration re semble those seen in development? Questions like these remain open, particularly in relation to the mammalian central nervous system and to the effects of lesions or disease. The first chapters of this volume are concerned primarily with normal and abnormal development of the nervous system. New concepts have emerged over the past few years as a result of experiments made on the development of the higher nervous system in mammals. Thus, the principles of cell death, competition, selective retraction of specific processes, and the effects of abnormalities on the development of the rest of the system have now been extensively investigated. In addition, considerable information is available about biochemical changes during normal and abnormal development in the human. At the other end of the scale, in invertebrates it is now possible to follow cell lineage and to define the origin and fate of a sin gle neuron of known function together with its processes. While an understanding of development is clearly important for studying basic mechanisms of repair and regeneration, one cannot expect the processes to be identical or even comparable in the two situations. For example, cell migration, guidance by radial glial fibers, selective cell death, and the critical periods for competition, sprouting, and retraction observed in the visual system can hardly playa part in repair."

Applications of synchrotron radiation in physics, chemistry, materials science, and biology has now matured from an exotic experimental field into a well-established area of science. The spectroscopy of molecules and molecular adsorbates on surfaces is one area of science, where, in the past, synchrotron-radiation-related studies had made an impact on understanding the ground-state properties as well as the dynamics. With the new high-brightness synchrotron-radiation sources ahead, this will certainly continue to be a field of very active research. This quasi-monograph reviews the current state of the field for both, the active research scientist, and the new graduate student wishing to become acquainted with this field of research.

Surface Science is understood as a relatively young scientific discipline, concerned with the physical and chemical properties of phenomena on clean and covered solid surfaces, studied under a variety of conditions. The adsorption of atoms and molecules on solid surfaces is, for example, such a condition, connected with more or less drastic changes of all surface properties. An adsorption event is frequently observed in nature and found to be of technical importance in many industrial processes. For this reason, Surface Science is interdisciplinary by its very nature, and as such an important intermediary between fundamental and applied research.