The 1988 Summer School on New Aspects of Nuclear Dynamics took place in the style that by now has become a tradition: a series of lectures by well known scientists on modem topics of nuclear physics, where special emphasis is placed on the didactic aspects of the lectures. In the past few years, we have witnessed a rapid evolution of the field of nuclear physics towards novel directions of research. This development is accompanied by the construction of some of the largest experimental facilities ever built for nuclear research. The subjects covered by the Summer School focussed on two main issues currently under active investigation and which will be pursued with the new facilities: the transition from nucleonic to quark degrees of freedom in the decription of nuclear reactions, and the behavior of nuclear matter as one approaches extreme densities and temperatures. These topics in many respects go beyond traditional nuclear physics and the speakers therefore also included high energy physicists. From the response of the participants it was clear that the program of the school filled a gap in the curriculum of many students. We wish to thank all the speakers for their well organized lectures, which were nicely geared to the level of the school, and for spending extra time on problem sessions and extensive discussions. The organization of this Summer School was made possible by substantial support from the Science Committee of the North Atlantic Treaty Organization.

The 1985 Summer School on Nuclear Dynamics, organized by the Nuclear Physics Division of the Netherlands' Physical Society, was the sixth in a series that started in 1963. This year's topic has been nuclear dynamics rather than nuclear structure as in the foregoing years. This change reflects a shift in focus to nuclear processes at higher energy, or, more generally, to nuclear processes under less traditional circumstances. For many years nuclear physics has been restricted to the domain of the ground state and excited states of low energy. The boundaries between nuclear physics and high-energy physics are rapidly disappearing, however, and the future will presumably show that the two fields of research will contribute to one another. With the advent of a new generation of heavy-ion and electron accelerators research activities on various new aspects of nuclear dynamics over a wide range of energies have become possible. This research focuses in particular on nonnucleonic degrees of freedom and on nuclear matter under extreme conditions, which require the explicit introduction of quarks into the description of nuclear reactions. Mean-field formulations are no longer adequate for the description of nucleus nucleus collisions at high nucleon energies as the nucleon-nucleon collisions begin to dominate. Novel dynamical theories are being developed, such as those based upon the Boltzmann equation or hadrodynamic models. The vitality of nuclear physics was clearly demonstrated by the enthusiastic lecturers at this summer school. They presented a series of clear and thorough courses on the subjects above."

The last decade has been witness to many exciting and rapid developments in the fields of Nuclear Physics and Intermediate Energy Physics, the interface between Nuclear and Elementary Particle Physics. These developments involved to a large extent the sub nucleonic degrees of freedom in nuclei. In deep inelastic lepton scattering from nuclei, for example, it was observed that the quark structure of the nucleon is influenced by the nuclear medium. Also, the spin-dependent structure function of the nucleon was found to differ from sum rules based on SU(3) symmetry, a discrepancy referred to as the "spin crisis". In pion electroproduction at threshold and in the production of pions and other mesons in heavy ion collisions at intermediate energies interesting experimental results have been obtained, which triggered lively theoretical discussions. Furthermore, the search for the quark-gluon plasma phase of hadronic matter, a phase that is supposed to have existed in the first few seconds of the Big Bang, has been intensified. Not only were these developments accompanied by technical developments, such as the building of new experimental facilities, but also extensive theoretical efforts have been directed towards understanding these phenomena. These concerted efforts will hopefully lead to an understanding of the transition from the non-perturbative QCD regime to the perturbative one, in which the quark structure of nucleons is better understood. All of the aforementioned developments occur at a high pace, making it difficult to incorporate them into the courses offered to advanced students.

In many areas of physics, such as astrophysics, solid-state physics, nuclear physics and particle physics, a major outstanding problem is a better understanding of corre lation phenomena. While in most cases the average properties of a system are rather well understood, the correlations and the resulting clustering are poorly understood. They are reflections of the force mediating the interaction among the constituents and play essential roles in determining the structure of a physical system. At the largest scales, in astrophysics, it has recently been realized that there are huge voids in space and almost all matter is concentrated on filaments, raising interesting questions concerning the origin of this clustering of matter. In nuclear physics corre lation phenomena are important in all its subfields. It has been realized that so-called fluctuations in the one-particle density, which are a manifestation of nucleon-nucleon correlations, are crucial. These are important for an understanding of heavy-ion reac tions. This is the subject of modern quantum transport theories. Correlations are also crucial in the description of the high momentum components as observed in quasi-elastic knock-out reactions."