Realizing the need of interaction between universities and research groups in industry, the European Consortium for Mathematics in Industry (ECMI) was founded in 1986 by mathematicians from ten European universities. Since then it has been continuously extending and now it involves about all Euro pean countries. The aims of ECMI are * To promote the use of mathematical models in industry. * To educate industrial mathematicians to meet the growing demand for such experts. * To operate on a European Scale. Mathematics, as the language of the sciences, has always played an im portant role in technology, and now is applied also to a variety of problems in commerce and the environment. European industry is increasingly becoming dependent on high technology and the need for mathematical expertise in both research and development can only grow. These new demands on mathematics have stimulated academic interest in Industrial Mathematics and many mathematical groups world-wide are committed to interaction with industry as part of their research activities. ECMI was founded with the intention of offering its collective knowledge and expertise to European Industry. The experience of ECMI members is that similar technical problems are encountered by different companies in different countries. It is also true that the same mathematical expertise may often be used in differing industrial applications.

In recent years the subject of relativistic fluid dynamics has found substantial applications in astrophysics and cosmology (theories of gravitational collapse, models of neutron stars, galaxy formation), as well as in plasma physics (relativistic fluids have been considered as models for relativistic particle beams) and nuclear physics (relativistic fluids are currently used in the analysis of the heavy ion reactions). Modern methods of analysis and differential geometry have now also been introduced. The International C.I.M.E. Course brought together expertise and interest from several areas (astrophysics, plasma physics, nuclear physics, mathematical methods) to create an appropriate arena for discussion and exchange of ideas. The main lecture courses introduced the most significant aspects of the subject and were delivered by leading specialists. The notes of these have been written up for this volume and constitute an up-to-date and thorough treatment of these topics. Several contributions from the seminars on specialized topics of complementary interest to the courses are also included.