This volume contains the detailed text of the major lectures and the abstracts of the lectures delivered during the seminar sessions. The subject of our NATO Advanced Study Institute in 1981 was the Application of Modern Dynamics to Celestial Mechanics and Astrodynamics. This Preface will first explain the terminology, then it will review shortly the content of the lectures and will outline how all this was made possible and, finally, it will disclose our future aspirations. Periodicity is an extremely important concept in our field, therefore, it should not be unexpected that our NATO Advanced Study Institute is enjoying a period of three years. Since 1972 we conducted four Institutes with increasing interest and en thusiasm displayed by the participants, lecturers and by this Director. Celestial Mechanics or Dynamical Astronomy is part of Astronomy dealing mostly with the motion of natural celestial bodies. Astrodynamics or Orbital Mechanics is the application of dynamics to problems of Space Engineering and it treats mostly the dynamical behavior of artificial satellites and space probes. The underlying mathematical and dynamical principles are, of course, the same for Celestial Mechanics and for Astrodynamics. This Director of the Institute and Editor of the Proceedings was extremely fortunate to have obtained the cooperation of out standing lecturers who were clear, thorough, understandable, patient to answer questions, but above all, had knowledge of the ix V. Szebehely (ed.). Applications of Modern Dynamics to Celestial Mechanics and Astrodynamics. ix-x.

Astronomy and Astrophysics Abstracts, which has appeared in semi-annual volumes since 1969, is devoted to the recording, summarizing and indexing of astronomical publications throughout the world. It is prepared under the auspices of the International Astronomical Union (according to a resolution adopted at the 14th General Assembly in 1970). Astronomy and Astrophysics Abstracts aims to present a comprehensive documenta tion of literature in all fields of astronomy and astrophysics. Every effort will be made to ensure that the average time interval between the date of receipt of the original literature and publication of the abstracts will not exceed eight months. This time interval is near to that achieved by monthly abstracting journals, compared to which our system of accumu lating abstracts for about six months offers the advantage of greater convenience for the user. Volume 31 contains literature published in 1982 and received before July 15, 1982; some older literature which was received late and which is not recorded in earlier volumes is also included. We acknowledge with thanks contributions to this volume by Dr. J. Bouska, Prague, who surveyed journals and publications in Czech and supplied us with abstracts in English .

It is this editor's distinct pleasure to offer to the readership the text of the lectures presented at our recent NATO Advanced Study Institute held in Cortina d'Ampezzo, Italy between August 6 and August 17, 1984. The invited lectures are printed in their entirety while the seminar contributions are presented as abstracts. Our Advanced Study Institutes were originated in 1972 and the reader, familiar with periodic phenomena, so important in Celestial Mechanics, will easily establish the fact that this Institute was our fifth one in the series. We dedicated the Institute to the subject of stability which itself is a humbling experience since it encompasses all fields of sciences and it is a basic element of human culture. The many definitions in existence and their practical applications could easily fill another volume. It is known in this field that it is easy to deliver lectures or write papers on stability as long as the definition of stability is carefully avoided. On the other hand, if one selects a definition, he might be criticized for using that definition and not another one. In this volume we carefully defined the specific concept of stability used in every lecture. If the reader wishes to introduce other definitions we feel that he should be entirely free and we encourage him to do so. It is also known that certain sta bility definitions and concepts are more applicable to certain given fields than to others.

Long established as one of the premier references in the fields of astronomy, planetary science, and physics, the fourth edition of Orbital Motion continues to offer comprehensive coverage of the analytical methods of classical celestial mechanics while introducing the recent numerical experiments on the orbital evolution of gravitating masses and the astrodynamics of artificial satellites and interplanetary probes. Following detailed reviews of earlier editions by distinguished lecturers in the USA and Europe, the author has carefully revised and updated this edition. Each chapter provides a thorough introduction to prepare you for more complex concepts, reflecting a consistent perspective and cohesive organization that is used throughout the book. A noted expert in the field, the author not only discusses fundamental concepts, but also offers analyses of more complex topics, such as modern galactic studies and dynamical parallaxes. New to the Fourth Edition: * Numerous updates and reorganization of all chapters to encompass new methods * New results from recent work in areas such as satellite dynamics * New chapter on the Caledonian symmetrical n-body problem Extending its coverage to meet a growing need for this subject in satellite and aerospace engineering, Orbital Motion, Fourth Edition remains a top reference for postgraduate and advanced undergraduate students, professionals such as engineers, and serious amateur astronomers.

The dynamics of physical, chemical, biological, or fluid systems generally must be described by nonlinear models, whose detailed mathematical solutions are not obtainable. To understand some aspects of such dynamics, various complementary methods and viewpoints are of crucial importance. In this book the perspectives generated by analytical, topological and computational methods, and interplays between them, are developed in a variety of contexts. This book is a comprehensive introduction to this field, suited to a broad readership, and reflecting a wide range of applications. Some of the concepts considered are: topological equivalence; embeddings; dimensions and fractals; Poincaré maps and map-dynamics; empirical computational sciences vis-á-vis mathematics; Ulam's synergetics; Turing's instability and dissipative structures; chaos; dynamic entropies; Lorenz and Rossler models; predator-prey and replicator models; FPU and KAM phenomena; solitons and nonsolitons; coupled maps and pattern dynamics; cellular automata.

The dynamics of physical, chemical, biological or fluid systems generally must be described by nonlinear models, whose detailed mathematical solutions are not obtainable. To understand some aspects of such dynamics, various complementary methods and viewpoints are of crucial importance. The presentation and style is intended to stimulate the reader's imagination to apply these methods to a host of problems and situations.

Proceedings of the 74th Colloquium of the International Astronomical Union held in Gerakini Chalkidiki, Greece, August 30-September 2, 1982

The reader will find in this volume the Proceedings of the NATO Advanced Study Institute held in Cortina d'Ampezzo, Italy between August 3 and August 13, 1987 under the title "Long Term Dynamical Behaviour of Natural and Artificial N-body Systems". The Institute was the latest in a series held in 1972, 1975, 1978, 1981, 1984 in dynamical astronomy, theoretical mechanics and celestial mechanics under the Directorship of Professor Victor Szebehely. These previous institutes, held in high esteem by the international community of research workers, have resulted in a series of well-received and valuable Proceedings. In correspondence with Professor Szebehely and in long discussions with him in Colorado in August 1985, I agreed to his request that I undertake the preparation of a new ASI. I was happy to do so knowing I could call upon his vast experience in overseeing such ASI's. The last quarter century has been a period in which increasingly rapid progress has been made in celestial mechanics and related subjects not only because of the appearance of new problems urgently requiring solution but also because of the advent of new analytical techniques and powerful computer hardware and software.

Half a century ago, S. Chandrasekhar wrote these words in the preface to his l celebrated and successful book: In this monograph an attempt has been made to present the theory of stellar dy namics as a branch of classical dynamics - a discipline in the same general category as celestial mechanics. [ ... J Indeed, several of the problems of modern stellar dy namical theory are so severely classical that it is difficult to believe that they are not already discussed, for example, in Jacobi's Vorlesungen. Since then, stellar dynamics has developed in several directions and at var ious levels, basically three viewpoints remaining from which to look at the problems encountered in the interpretation of the phenomenology. Roughly speaking, we can say that a stellar system (cluster, galaxy, etc.) can be con sidered from the point of view of celestial mechanics (the N-body problem with N » 1), fluid mechanics (the system is represented by a material con tinuum), or statistical mechanics (one defines a distribution function for the positions and the states of motion of the components of the system).

The reader will find in this volume the Proceedings of the NATO Advanced Study Institute held in Maratea-Acquafredda, Italy, between June 29 and July 12, 1997, entitledTHE DYNAMICS OF SMALL BODIES IN THE SOLAR SYSTEM: A MAJOR KEY TO SOLAR SYSTEM STUDIES . This Advanced Study Institute was the latest in the 'Cortina' series of NATO ASI's begun in the early 1970's firstly under the directorship of Professor Victor Szebehely and subsequently under Professor Archie Roy. All, except the latest, were held at the Antonelli Institute, Cortina d'Ampezzo, Italy. Many of those now active in the field made their first international contacts at these Institutes. The Institutes bring together many of the brightest of our young people working in dynamical astronomy, celestial mechanics and space science, enabling them to obtain an up-to-date synoptic view of their subjects delivered by lecturers of high international reputation. The proceedings from these institutes have been well-received in the internationalcommunity of research workers in the disciplines studied. The present institute included 15 series of lectures given by invited speakers and some 45 presentations made by the other participants. The majority of these contributions are includedinthese proceedings.