The proceedings of this workshop should probably be prefaced with a few words on some of the more confusing jargon. The phrases "Very Low-Mass star" , "VLM star", or simply "VLM" are now used fairly uniformly by as tronomers studying the stars at the bottom of the hydrogen-burning stellar main sequence - unfortunately, however, there is no clear definition as to what constitutes a VLM star. The reader should be warned that VLM stars are variously considered to be stars with; masses less than 0.3M ; masses 0 less than 0.1M ; spectra later than about M6-7; luminosities fainter than 0 Mv = 15; or luminosities fainter than Mbol = 12. The important features of a VLM star, however, would seem to be (1) that it is about as faint as a star can be, and (2) that it still remains a star (ie. it still burns hydrogen) . All of the above criteria, therefore, would seem to qualify an object as a VLM star, and requiring a more stringent definition is probably quibbling.

The 14 papers in this collection discuss recent progress in areas such as mixing in stellar interiors, redistribution and loss of angular momentum, emphasizing in particular the effects of turbulence. An introductory review by E. Schatzman, to whom this volume is dedicated, is followed by three sections: observational facts (surface abundances, stellar rotation, loss of mass and angular momentum, etc.), physical knowledge (mass transport and mixing by waves, turbulent transport, fast dynamo action, etc.), and the interpretation of observations.

Large-scale structures in the universe are becoming ever more important in modern astrophysics. This volume is dedicated to the memory of the late astrophysicist Fritz Zwicky and presents 34 lectures dealing with observational and theoretical aspects of the morphology of the universe. Reports on the distribution, properties and evolution of groups, clusters and superclusters of galaxies, as well as theoretical attempts to explain these findings using such ideas as biased galaxy formation and cold dark matter, are presented here for researchers and students of astronomy and astrophysics.

volume XIX A of IAU Transactions contains the reports by Presidents of Commissions, covering the period July 1981 - June 1984. The topics of IAU Commissions deal with all of contemporary astronomy and the present volume therefore constitutes an exhaustive and unique record of astronomical research during this interval. It is particularly useful for astronomers and other scientists who want to gain an overview of a certain field, not necessarily near their own research area. Each Commission President was requested, by early 1984, to begin prep arations for the compilation of his/her Commission report. All members of Commissions were asked to supply details about their individual research pro grammes. The ensuing, very substantial task of concatenating was undertaken in late 1984 by the Presidents, often supported by a team of authors, all recog nized authorities in their fields. In order to preserve some measure of uni formity - which is in any case very difficult with so many authors - editorial guidelines were sent to Presidents, including the number of pages allotted to each Commission.

This publication is a result of three meetings, each 5 days long, held at the Goddard Space Flight Center on January 24-28, 1983, June 8-14, 1983, and February 13-17, 1984. The meetings were held in the interim between the full operations of the Solar Maximum Mission (SMM) in 1980, and the renewed operations after its repair in orbit in April 1984. Their general objectives were as follows: o Synthesize flare studies after three years of SMM data analysis. Many analyses of individual flares and individual phenomena, often jointly across many data sources had been published, but a need existed for a broader synthesis and updating of our understanding of solar flares since the Skylab Flare Workshops held several years earlier. o Encourage a broader participation in the SMM data anlysis and combine this more fully with theory and other data sources--data obtained with other spacecraft such as the HINOTORI, P78-1, and ISEE-3 spacecrafts, and with the Very Large Array (VLA) and many other ground-based instruments. Many coordinated data sets, unprecedented in their breadth of coverage and multiplicity of sources, had been obtained within the structure of the Solar Maximum Year (SMY). o Stimulate joint studies, and publication in the general scientific literature. The intended primary benefit was for informal collaborations to be started or broadened at the Workshops with subsequent publications. o Provide a special publication resulting from this Workshop. o Provide a starting point of understanding for planning renewed full observations with the repaired SMM.

For some time to come, this book should be the main source for research in prominences. It surveys the results of the past years, including the "Hvar Reference Atmosphere", which was developed by a panel as a model for quiescent prominences. The reader will find papers on the formation of and physical conditions in prominences, on magnetic fields, on mass motion and energy flow, and on the prominence-corona interface.

ESO's new and exciting telescope, the VLT in Chile, will certainly bring a host of new results in optical astronomy for the years to come. This workshop surveys a large variety of possible observations and the needed instrumentation. It is an exciting overview of front research in astronomy rarely published before. The book covers the whole gamut of optical-IR astronomy from the solar system, search for planets in nearby stars, physics of galactic stars and clusters, galactic structure, structure of nearby galaxies, AGN and quasars, clusters of galaxies, to large structure and cosmology. Furthermore it summarizes the two panel discussions.

The ESO jIAC Workshop on Quasar Hosts was held in Puerto de la Cruz, Tenerife, from 24 to 27 September 1996 in the Conference Centre of the Ca- bildo Insular de Tenerife. The four days of the meeting were filled with fasci- nating new results and interesting discussions, and ranged from the centre of our own galaxy to some of the most distant objects known in the universe. Quasar Host studies are going through an exciting time, and are benefiting from new facilities, including the refurbished HST and the Keck, and from novel techniques, including adaptive optics and deconvolution methods. We also saw the first of hopefully many results from the ISO satellite. These re- sults were presented during the many sessions and discussed in the gardens over coffee, and on the bus during our tour of the Canaries Observatories. We would very much like to thank the secretaries of ESO and lAC, Christina Stoffer, Pamela Bristow, Monica Murphy, Judith de Araoz, and Beatriz Mederos, who we depended on for their expertise and efficiency. Our colleagues on the scientific organising committee, Phil Crane, Bob Fosbury, Marie-Helene Ulrich, Peter Shaver and Jose Rodriguez-Espinosa, deserve considerable thanks for their contributions to the programme. We must also thank the local organising committee, Fernando Cabrera- Guerra, Monica Murphy, Ismael Perez-Fournon, Ana Perez-Garcia, Luis Ramirez-Castro, and Montserrat Villar-Martin, for all their efforts in making sure things ran smoothly on the day.

An exploration of the intersection of particle physics, astrophysics, and cosmology known as astroparticle physics. Extreme electromagnetic conditions present in puslars and other stars allow for investigations of the role of quantum processes in the dynamics of astrophysical objects and in the early Universe. Based in part on the authors' own work, this book systematically describes several methods of calculation of the effects of strong electromagnetic fields in quantum processes using analytical solutions of the Dirac equation and Feynmann diagrams at both the loop and tree levels. The consideration is emphasized at the two limiting cases: the case of a very strong magnetic field, and the case of a crossed field. The presentation will appeal to graduate students of theoretical physics with prior understanding of Quantum Field Theory (QFT) and the Standard Model of Electroweak Interactions, as well as specialists in QFT wishing to know more about the problems of quantum phenomena in external electomagnetic fields.

The"4thCologne-Bonn-ZermattSymposium: TheDenseInterstellarMedium in Galaxies" took place in Zermatt, Switzerland, from September 22nd to 26th, 2003. This symposium continued the series of conferences on the dense interstellar medium which has been organized every 5 years since 1988 by the I. Physikalisches Institut der Unversit] at ] zuKoln. ] Re?ecting the by now well established and fruitful collaboration between the MPI ffur ] ] Radioastronomie, the Radioastronomisches Institut der Universit] at ] Bonn and the I. Physikal- ches Institut der Universit] at ] zu Koln ] in the context of the Sonderforschun- bereich 494 "The Evolution of Interstellar Matter: THz-Spectroscopy in the Laboratory and in Space," the symposium is now organized jointly by these three institutes. The conference covered a wide range of topics: starting at the largest scales and earliest times in the history of the Universe, it focussed next on galaxy evolution and their structure and dynamics. New and very exciting results on the black hole in the center of the Milky Way and the violent ISM in its immediate vicinity were presented. It continued on the cosmic cycle of star formation and evolution, and reached down to the microphysical p- cesses determining the physical and chemical conditions of the interstellar matter as the important agent for this cosmic cycle."

What is unorthodox in this book? Much has happened in the last few years, especially in terms of the somewhat surpris ing rate at which the theories presented herein have been gaining increasing acceptance and support even by the most skeptical professionals. Nevertheless, the purpose of this up-dated Preface is not to tell the biographical and acceptance story behind this book, but to bring together some non-physical and non technical conclusions for those readers who find the physico-mathematical sections of this book too difficult to follow. A secondary purpose is to present here some newer conclu sions, especially in general philosophy and in aesthetics. Yet, the main physico philosophical conclusions presented in this book are not to be summarized here. For that purpose one must tum to the text itself. * * * The theories presented here have been developed in total isolation. They were never presented in "professional conferences," as most current writers do. Whether or not that was important remains to be seen. Hence, all I can state to critics and enthusiastic follow ers alike is the fact that I do not belong to any 'formal discipline', 'pressure group', or 'pro fessional organization'."

"Stellar Physics" is a an outstanding book in the growing body of literature on star formation and evolution. Not only does the author, a leading expert in the field, very thoroughly present the current state of knowledge on stellar physics, but he handles with equal care the many problems that this field of research still faces. A bibliography with well over 1000 entries makes this book an unparalleled reference source.
"Stellar Evolution and Stability" is the second of two volumes and can be read, as can the first volume "Fundamental Concepts and Stellar Equilibrium," as a largely independent work. It traces in great detail the evolution of protostars towards the main sequence and beyond this to the last stage of stellar evolution, with the corresponding vast range from white dwarfs to supernovae explosions, gamma-ray bursts and black hole formation. The book concludes with special chapters on the dynamical, thermal and pulsing stability of stars.

This second edition is carefully updated in the areas of pre-supernova models, magnetorotational supernovae, and the theory of accretion disks around black holes. Additional sections have been added on strange quark stars, jet formation and collimation, radiation-driven winds in strong gravitational fields and gamma-ray bursts.

Review: Review of the first edition: 'A fresh and exciting introduction to modern galactic physics on the grand scale, and of its connections to other broad domains of contemporary physics. Graduate students in particular, will appreciate the clarity of presentation.' Bruno Coppi, Massachusetts Institute of Technology Review of the first edition: 'This book fills a major need for a graduate-level, physically-based introduction to galaxies, and will be of a very wide appeal as a course text. The original approach leads to a rich physical intuition of real kinematical systems. A particular strength is the detailed analysis of the limitations of current methods and theories.' Gerry Gilmore, University of Cambridge Review of the first edition: 'Giuseppe Bertin's Dynamics of Galaxies is an elucidating account of a graduate course given by Bertin over the past two decades ... His] book is particularly useful for students interested in mathematical methods of galactic dynamics. Bertin's comparisons between galactic dynamics and plasma physics are also innovative and illustrative.' Debra Elmegreen, Physics Today

'Fractal geometry addressesitselfto questions that many people have been asking themselves. It con cerns an aspect of Nature that almost everybody had been conscious of, but could not address in a formal fashion. ' 'Fractal geometry seems to be the proper language to describe the complezity of many very compli cated shapes around us. ' (Mandelbrot, 1990a) 'I believe that fractals respond to a profound un easiness in man. ' (Mandelbrot, 1990b) The catchword fractal, ever since it was coined by Mandelbrot (1975) to refer to a class of abstract mathematical objects that were already known at the turn ofthe 19th century, has found an unprecedented resonance both inside and outside the scientific community. Fractal concepts, far more than the concepts of catastrophe theory introduced a few years earlier, are currently being applied not only in the physical sciences, but also in biology and medicine (Goldberger and West 1987). In the mid-eighties, Kadanoff (1986) asked the question: 'Why all the fuss about /ractals' '. He offered a twofold answer: in the first place, it is 'because of the practical, technological importance of fractal objects'. Indeed he emphasised the relevance of these structures for materials scientists and oil drilling engineers, in search of structures with novel properties, or models for the flow of oil through the soil. His second answer was: 'Because of the intellectual interest of fractals '."

The auroral emissions in the upper atmosphere of the polar regions of the Earth are evidence of the capture of energetic particles from the Sun, streaming by the Earth as the solar wind. These auroral emissions, then, are a window to outer space, and can provide us with valuable information about electrodynamic coupling processes between the solar wind and the Earth's ionosphere and upper atmosphere. Studying the physics of these phenomena extends our understanding of our plasma universe.

Ground-based remote-sensing techniques, able to monitor continuously the variations in the signatures of aurorae, in combination with in-situ satellite and rocket measurements, promise to advance dramatically our understanding of the physical processes taking place at the interface of the atmospheres of the Earth and the Sun. Decoding their complexity brings us closer to reliable prediction of communication environments, especially at high latitudes. This understanding, in turn, will help us resolve problems of communication and navigation across polar regions.

Aurorae have been the object of wonder and scientific curiosity for centuries. Only recently, however, have we been able to detect, with sensitive instrumentation, noontime aurorae, and persistent aurorae deep within the polar cap. This book is the first to provide a morphological and theoretical framework for understanding these dayside and polar cap aurorae.

The book also communicates the excitement of discovery, as it details the nature of these newly revealed auroral displays. It is a fascinating voyage of exploration, one appropriate for students of nature, wherever and whoever they may be.

Transitions from the innermost shells of iron, especially the K- and L-shelllines, provide a powerful tool for probing the physical characteristics of hot plasmas in X-ray sources. Their strength and purity allow important conclusions to be drawn even with modest energy resolution. They should also help in studying the regions around black holes and neutron stars. In this book the state of the art and themost recent theoretical and experimental observations are presented. The book will be a valuable source for future satellite missions. It addresses both researchers and graduate students in astrophysics.

This is a fair overview of the basic problems in Solar Physics. The authors address not only the physics that is well understood but also discuss many open questions. The lecturers' involvement in the SOHO mission guarantees a modern and up-to-date analysis of observational data and makes this volume an extremely valuable source for further research.

At this time when astronomers are being surprised by the discovery of objects which emit a fabulously large amount of energy, that is the quasi-stellar radio sources and the quasi-stellar galaxies, and when by the means of space vehicles X rays, gamma rays and cosmic rays are being observed to come from the depths of interstellar space, one may ask why write a book about stars. Stars seem to be almost incidental when one looks at the universe in terms of exceedingly great energies. Nevertheless, stars exist. They are accessible to study and they have not yet revealed all their secrets. This is enough to arouse interest and to cause one to try to find answers to the questions which arise. The early type stars are particularly interesting because they are spendthrift stars pouring out their energy at a great rate. But their brilliance is also their undoing. They must evolve rather quickly, on an astrophysical scale. Thus by studying these stars we are studying a population in change. The implications from the local and from the cosmological viewpoint are important if one wishes to understand the details of stellar evolution and of galactic structure. Perhaps one of the simplest reasons for writing a book about the early type stars is to see if some of the conundrums pre sented by the spectra of these stars can be unravelled when all the available infor mation is brought together."

This volume provides an overview of our current understanding of the physics related to: coronal structures and coronal heating; large-scale coronal shock waves and coronal mass ejections; particle beams in the solar corona and in the interplanetary medium; and explosive energy-release phenomena and particle acceleration. The different articles give a well-balanced presentation of relevant observations based upon various techniques, models and theories, providing a global view of these phenomena and of the underlying physics. In-situ measurements of particles and waves with ULYSSES and WIND and spectral and imaging data from SOHO and YOHKOH provide an unprecedented richness of relevant data. For their better understanding, radio observations - also included in this book - play a key role.

This volume brings together theoretical ideas on the plasma physics of both hot and dense plasmas in the solar atmosphere and similar physics applied to the tenuous and cooler plasmas found in the heliosphere. It is complemented by recent observations. Helioseismology covers the solar interior and the neutrino problem. Solar and stellar activity cycles are addressed. The dynamics of magnetic flux tubes in the solar atmosphere and material flows through the chromosphere into the upper atmosphere are comprehensively reviewed. Energy release processes and the production of energetic particles are important to understanding events in the solar atmosphere and to the dynamics of the tenuous heliosphere. A glimpse of the future is offered by concluding chapters on new ground-based and space instrumentation.

This book contains the proceedings of a workshop held in Schloss Ringberg to assess developments in molecular cloud research over the last 25 years, and to discuss trends for future research in the field of molecular line astronomy. The topics include the morphology, formation, and lifetimes of molecular clouds, and their relation to star formation. Also, the chemical and isotopic content of these clouds is reviewed, and comparisons with molecular clouds in external galaxies are made. This rather complete survey of this important field of research addresses researchers in astronomy and students alike."

This is the first volume of a series on a regular up-to-date coverage of important developments in astronomy and astrophysics jointly published by ESO and Springer-Verlag. Here the reader finds a thorough review of the abundances of the elements up to Boron. Special emphasis is laid on primordial abundances of interest to cosmologists in particular, and on stellar production or destruction respectively. The articles written for researchers and graduate students cover theory and most recent data from telescope observations.

The most luminous compact objects are powered by accretion of mass. Accretion disks are the one common and fundamental element of these sources on widely different scales, ranging from close stellar binaries, galactic black holes and X-ray pulsars to active galactic nuclei (AGN). Key new developments in theory and observations, reviewed by experts in the field, are presented in this book. The contributions to the workshop cover the puzzles presented by the X-UV spectra of AGN and their variability, the recent numerical simulations of magnetic fields in disks, the remarkable behavior of the superluminal source 1915+105 and the "bursting pulsar" 1744-28, to mention a few of the topics.

'Dark energy' is the name given to the unknown cause of the Universe's accelerating expansion, which is one of the most significant and surprising discoveries in recent cosmology. Understanding this enigmatic ingredient of the Universe and its gravitational effects is a very active, and growing, field of research. In this volume, twelve world-leading authorities on the subject present the basic theoretical models that could explain dark energy, and the observational and experimental techniques employed to measure it. Covering the topic from its origin, through recent developments, to its future perspectives, this book provides a complete and comprehensive introduction to dark energy for a range of readers. It is ideal for physics graduate students who have just entered the field and researchers seeking an authoritative reference on the topic.