Molecular similarity has always been an important conceptual tool of chemists, yet systematic approaches to molecular similarity problems have only recently been recognized as a major contributor to our understanding of molecular properties. Advanced approaches to molecular similarity analysis have their foundation in quantum similarity measures, and are important direct or indirect contributors to some of the predictive theoretical, computational, and also experimental methods of modern chemistry. This volume provides a survey of the foundations and the contemporary mathematical and computational methodologies of molecular similarity approaches, where special emphasis is given to applications of similarity studies to a range of practical and industrially significant fields, such as pharmaceutical drug design. The authors of individual chapters are leading experts in various sub-fields of molecular similarity analysis and the related fundamental theoretical chemistry topics, as well as the relevant computational and experimental methodologies. Whereas in each chapter the emphasis is placed on a different area, nevertheless, the overall coverage and the wide scope of the book provides the reader with a general yet sufficiently detailed description that may serve as a good starting point for new studies and applications of molecular similarity approaches. The editors of this volume are grateful to the authors for their contributions, and hope that the readers will find this book a useful and motivating source of information in the rapidly growing field of molecular similarity analysis.

INSTEAD OF A "FESTSCHRIFT" In June 1998 Hans Primas turned 70 years old. Although he himself is not fond of jubilees and although he likes to play the decimal system of numbers down as contingent, this is nevertheless a suitable occasion to reflect on the professional work of one of the rare distinguished contempo rary scientists who attach equal importance to experimental and theoretical and conceptual lines of research. Hans Primas' interests have covered an enormous range: methods and instruments for nuclear magnetic resonance, theoretical chemistry, C* - and W* -algebraic formulations of quantum me chanics, the measurement problem and its various implications, holism and realism in quantum theory, theory reduction, the work and personality of Wolfgang Pauli, as well as Jungian psychology. In many of these fields he provided important and original food for thought, in some cases going far beyond the everyday business in the scien tific world. As is the case with other scientists who are conceptually inno vative, Hans Primas is read more than he is quoted. His influence is due to his writings. Even with the current flood of publications, he still performs the miracle of having scientists eagerly awaiting his next publication."

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.

At the end of the workshop on "New Theoretical Concepts in Physical Chemistry," one of the participants made an attempt to present a first impression of its achievements from his own personal standpoint. Appar ently his views reflected a general feeling, so that the organizers thought they would be suitable as a presentation of the proceedings for future readers. That is the background from which this foreword was born. The scope of the workshop is a very broad one. There are contribu tions from mathematics, physics, crystallography, chemistry and biology; the problems are approached either by means of axiomatic and rigorous methods, or at an empirical phenomenological level. This same diversifi cation can be found in the new basic concepts presented. Some arise from pure theoretical investigation in C*-algebra or in quantum probability theory; others from an analysis of very complex experimental data like nuclear energy levels, or processes on the frontier between classical and quantum physics; others again have their origin in the discovery of new ordered structures like the icosahedral crystal phases, or the knots of DNA molecules; others follow from the application of ideas like frac tals or chaos to new fields like spectral theory or chemical reactions. It is to be expected that readers will have to face the same sort of difficulties as did the participants in understanding such diverse languages, in applying themselves to subjects possibly far from their own experience, and in grasping highly sophisticated new concepts."

Molecular similarity has always been an important conceptual tool of chemists, yet systematic approaches to molecular similarity problems have only recently been recognized as a major contributor to our understanding of molecular properties. Advanced approaches to molecular similarity analysis have their foundation in quantum similarity measures, and are important direct or indirect contributors to some of the predictive theoretical, computational, and also experimental methods of modern chemistry. This volume provides a survey of the foundations and the contemporary mathematical and computational methodologies of molecular similarity approaches, where special emphasis is given to applications of similarity studies to a range of practical and industrially significant fields, such as pharmaceutical drug design. The authors of individual chapters are leading experts in various sub-fields of molecular similarity analysis and the related fundamental theoretical chemistry topics, as well as the relevant computational and experimental methodologies. Whereas in each chapter the emphasis is placed on a different area, nevertheless, the overall coverage and the wide scope of the book provides the reader with a general yet sufficiently detailed description that may serve as a good starting point for new studies and applications of molecular similarity approaches. The editors of this volume are grateful to the authors for their contributions, and hope that the readers will find this book a useful and motivating source of information in the rapidly growing field of molecular similarity analysis.

Life must be understood as the result of evolution, and human life as the emergence of the species Sapiens from the genus Homo of the family of apes. If the emergence of human life as an evolutionary fact is coupled with the notion of social life, we are referred to the constructive production of human life forms, of which social participation is an integral part. On the one hand, participation is tied back to the phylogenesis of the species Sapiens, but on the other hand, it has to be newly acquired and practiced by every human being in the process of ontogenesis, depending on the environment. Participation in old age is a separate specification of the conditions of this process and can be illustrated on the basis of a large number of empirical findings.

Leben muss als Ergebnis der Evolution aufgefasst werden und menschliches Leben als die Entstehung der Art Sapiens aus der Gattung des Homo aus der Familie der Menschenaffen. Wird die Entstehung menschlichen Lebens als evolutionare Tatsache mit der Vorstellung sozialen Lebens gekoppelt, werden wir auf die konstruktive Hervorbringung der menschlichen Lebensformen verwiesen, deren integraler Bestandteil gesellschaflichte Teilhabe ist. Teilhabe ist einerseits an die Phylogenese der Art Sapiens ruckgebunden, muss andererseits aber von jedem Menschen in der Ontogenese neu erworben und praktiziert werden, wobei er auf Umwelt angewiesen ist. Teilhabe im Alter ist eine eigene Spezifikation der Bedingungen dieses Prozesses und lasst sich anhand einer Vielzahl von empirischen Befunden darstellen.

Das Buch entspringt zwei Vorlesungen, die Hans Primas an der ETH Zurich gehalten hat. Es vermittelt die Grundlagen der allgemeinen Spektroskopie und erarbeitet die dazu erforderlichen theoretischen Hilfsmittel: Thermostatik, statistische Mechanik, Dichteoperatoren, Dynamik offener Quantensysteme, lineare Antworttheorie. In den Anwendungen finden sich die Blochschen Gleichungen der Kernresonanz, Fermis /golden rule/, die Einsteinschen UEbergangswahrscheinlichkeiten, Linienverbreiterungen u.a.m. Der besondere Reiz der Darstellung liegt in dem sehr persoenlichen Zugang, Ergebnis einer jahrzehntelangen kritischen Auseinandersetzungen mit den theoretischen Grundlagen und einer herausragenden Literaturkenntnis in Mathematik und den theoretischen Naturwissenschaften.