This NATO Advanced Study Institute centered on large-scale molecular systems: Quantum mechanics, although providing a general framework for the description of matter, is not easily applicable to many concrete systems of interest; classical statistical methods, on the other hand, allow only a partial picture of the behaviour of large systems. The aim of the ASI was to present both aspects of the subject matter and to foster interaction between the scientists working in these important areas of theoretical physics and theoretical chemistry. The quantum-mechanical part was mostly based on the operator-algebraic formulation of quantum mechanics and comprised quantum statistics of infinite systems with special em phasis on macroscopic observables, equilibrium conditions, irreversibility on the one hand, symmetry breaking for molecules in the radiation field and macroscopic quantum phenomena in the theory of superconductivity (BCS-theory) on the other hand. In addition, phase-space methods for many-body systems were also presented. Statistical physics was the main topic in the other lectures of the School; much emphasis was put on the statistical features of macros copic ("large") systems, the lectures dealt with mass and energy transport im polymers, in gels and in microemulsions, with aggregation and growth phenomena, with relaxation in complex, correlated systems, with conduction and optical properties of polymers, and with the means of describing disordered systems, above all fractals and related hierarchical models.

The field of non-crystalline materials has seen the emergence of many challeng ing problems during its long history. In recent years, the interest in polymeric and biological disordered matter has stimulated new activities which in turn have enlarged the organic and inorganic glass community. The current research fields and recent progress have extended our knowledge of the rich phenomenol ogy of glassy systems, where the role of disorder is fundamental for the underlying microscopic dynamics. In addition, despite the lack of a unified theory, many interesting theoretical models have recently evolved. The present volume offers the reader a collection of topics representing the current state in the understanding of disorder effects as well as a survey of the basic problems and phenomena involved. The task of compiling a book devoted to disordered systems has benefited much from a seminar organized by the W.-E. Heraeus Foundation in Bad Honnef in April 1992, where we had the opportunity to discuss the project with most of the authors. Here we wish to thank the Heraeus Foundation for their support, and the authors and Springer-Verlag, especially Dr. Marion Hertel, for the pleasant cooperation."