In May 1986 a two-day workshop on Physical Processes in Comets, Stars and Active Galaxies was held at the Ringberg Castle near Lake Tegernsee, and this rather unusml. l collection of topics needs a few words of explanation. When we first thought of organizing a workshop on such a large variety of astrophysical objects our main motivation was to honor Rudolf Kippenhahn and Hermann Ulrich Schmidt on the occasion of their 60th birthdays, and we planned to cover at least a fraction of their fields of active research. We then realized immediately that despite the fact that the objects are so different, the physical processes involved are very much the same, and that it is this aspect of astrophysics which governed the scientific lives of both of our distinguished colleagues and friends and allowed them to make major contributions to all those fields. Apparently this viewpoint was shared by many colleagues and it was therefore not surprising that in response to our invitation everybody who had been invited agreed to come and to present a talk. The workshop then turned out to be a real success. In contrast to highly specialized conferences, fundamental problems as well as very recent developments were discussed and the participants appreciated the opportunity to exchange ideas.