I have been asked by Professor Kikuchi to write a foreword for this interesting book on Dusty Plasmas and other electrical phenomena. This was a somewhat daunting task due to the wide range of topics covered. In what follows I have attempted to summarize most of these topics; for this purpose I have divided them into four groups, namely (a) Dusty Plasmas, (b) The Electrical Environment, (c) Lightning and (d) The Noise Environment. I hope that I have succeeded. in indicating that each section contains much that is of great interest. It is perhaps unnecessary for me to point out that the book contains subjects which are at an exciting and important stage in their development. (a) Dusty Plasmas The subject of dusty plasmas is one of great interest. Dust particles in interplanetary space, within comets, in inter-stellar space and at ever greater distances will in general be charged. The plasma environment will ensure this, bombarding electrons will charge up the particle until it assumes a "floating potential," although time variation can occur. Ultra violet radiation can cause photoemission and in certain cases field emission is a possibility. The motion of the particles will be determined by electric and magnetic fields together with gravity. If the density of charged grains becomes sufficiently high the grains will interact with each other and collective behaviour will ensue. This newly evolving subject entails the study of all kinds of plasma waves.

Modem dynamics is increasingly participating in the solution of problems raised by as tronomical observations. This new relationship is being fostered on one side by the im provements in the observations, which in recent years contributed several discoveries of new systems, such as the objects in the Kuiper belt, the pulsar and star companions, to speak only of the most striking ones, and, on the other hand, by the progresses in modem dynamics. The progresses in modem dynamics are due to two factors: the dissemination of fast computers, allowing the numerical studies of very complex systems by a large number of scientists, and the improvement in our understanding of the complex behaviour of Hamiltonian systems. KAM and Nekhorochev theories have shed a light on the subtle and surprizing interplays between regular and chaotic motions; numerical experiments and analytical approximations have shown how these peculiarities are indeed present in astronomically important systems and are instrumental in understanding their formation and evolution.

This volume comprises selected lectures presented in the Ninth Course of the International School ofCosmic-Ray Astrophysics held at the Ettore Majorana Centre in Erice, Sicily, May 7-18,1994. Director ofthe Centre is A. Zichichi, assisted by M. Zaini. Director ofthe School is M. M. Shapiro. 1. P. Wefel was co-director of the Ninth Course, which was also a NATO Advanced Study Institute (ASI), and NATO support is gratefully acknowledged. Devoted to problems and prospects in high-energy astrophysics and cosmology, the major areas explored in this course were: gamma-ray, X-ray, and neutrino astronomies; cosmic rays; pulsars and supernova remnants; and cosmology, as well as cosmogony. Among the principal developments in gamma-ray astrophysics were those generated by the Compton Gamma Ray Observatory. Cosmic neutrinos at MeV energies, i.e., those from the sun and from Supernova 1987a, were discussed, as well as neutrino masses in astrophysics. The source composition ofcosmic rays, and extensive air shower experiments, received special attention. The early universe according to COBE data, and as viewed by theorists ofcosmology, was reviewed. Finally, the connections with particle physics occasioned a timely description ofthe Standard Model ofelementary particles.

This volume is based on the lectures given at the First Inter University Graduate School on Gravitation and Cosmology organized by IUCAA, Pune, in 1989. This series of Schools have been carefully planned to provide a sound background and preparation for students embarking on research in these and related topics. Consequently, the contents of these lectures have been meticulously selected and arranged. The topics in the present volume offer a firm mathematical foundation for a number of subjects to be de veloped later. These include Geometrical Methods for Physics, Quantum Field Theory Methods and Relativistic Cosmology. The style of the book is pedagogical and should appeal to students and research workers attempt ing to learn the modern techniques involved. A number of specially selected problems with hints and solutions have been included to assist the reader in achieving mastery of the topics. We decided to bring out this volume containing the lecture notes since we felt that they would be useful to a wider community of research workers, many of whom could not participate in the school. We thank all the lecturers for their meticulous lectures, the enthusiasm they brought to the discussions and for kindly writing up their lecture notes. It is a pleasure to thank G. Manjunatha for his meticulous assistence over a long period, in preparing this volume for publication."

Stephen Webb, author of WHERE IS EVERYBODY?, takes the interested amateur on a thrilling and enlightening tour of the amazing, even bizarre, new ideas of modern physics, including alternatives to the Big Bang, parallel universes, and an imaginary trip to the other side of the black hole.

This book reflects our own struggle to understand the semiclassical behaviour of quantized fields in the presence of boundaries. Along many years, motivated by the problems of quantum cosmology and quantum field theory, we have studied in detail the one-loop properties of massless spin-l/2 fields, Euclidean Maxwell the ory, gravitino potentials and Euclidean quantum gravity. Hence our book begins with a review of the physical and mathematical motivations for studying physical theories in the presence of boundaries, with emphasis on electrostatics, vacuum v Maxwell theory and quantum cosmology. We then study the Feynman propagator in Minkowski space-time and in curved space-time. In the latter case, the corre sponding Schwinger-DeWitt asymptotic expansion is given. The following chapters are devoted to the standard theory of the effective action and the geometric im provement due to Vilkovisky, the manifestly covariant quantization of gauge fields, zeta-function regularization in mathematics and in quantum field theory, and the problem of boundary conditions in one-loop quantum theory. For this purpose, we study in detail Dirichlet, Neumann and Robin boundary conditions for scalar fields, local and non-local boundary conditions for massless spin-l/2 fields, mixed boundary conditions for gauge fields and gravitation. This is the content of Part I. Part II presents our investigations of Euclidean Maxwell theory, simple super gravity and Euclidean quantum gravity.

The modern Persian word for cosmology is "Keyhan-shenakht", which is also the title of a Persian book written more than 800 years ago. The same term can also be found in Old Persian. In spite of this old tradition, modern cosmology is a new~omer within the scientific disciplines in Iran. The cosmology community' is small and not yet well established. Given the spectacular recent advances in observational and theoretical cosmology, the large amount of new observational data which will become available in the near future, and the rapid expansion of the international cosmology community, it was realized that Iran should play a more active role in the exciting human endeavour which cosmology constitutes. This was the main motivation to establish a School on Cosmology in Iran. The plan is to hold a cosmology school every three years somewhere in Iran. The focus of this First School on Cosmology was chosen to be structure formation, a rapidly evolving cornerstone of modern cosmology. The topics of the school were selected in order to give both a broad overview of the current status of cosmological structure formation, and an in-depth dis cussion of the key issues theory of cosmological perturbations and analysis of cosmic microwave anisotropies. The lectures by Blanchard and Sarkar give an overview of homogeneous cosmological models and standard big bang cosmology. In his contribution, Padmanabhan presents a comprehen sive discussion of the growth of cosmological perturbations.

The Relativists and Cosmologists in India organized an international conference in Goa, India, in 1987, known as the International Conference on Gravitation and Cosmology (ICGC-87). Encouraged by the success of this conference it was decided to have such a meeting periodically, once in every four years. Accordingly, ICGC- 91 was held at the Physical Research Laboratory (PRL), Ahmedabad, India. The third International Conference on Gravitation and Cosmology, (ICGC-95) was held at the Inter-University centre for Astronomy and Astrophysics, IUCAA, Pune, India during December 13 - 19, 1995. This series of conferences is co-sponsored by the Indian Association for General Relativity and Gravitation (lAGRG). The Conference had 16 plenary lectures and five workshops altogether. There were three plenary lectures per day and two workshops running parallel each day. We were fortunate in getting plenary speakers who are leading experts in their respective fields drawn from all over the world. The conference was attended by about 105 persons from India and 55 from abroad. We thank all the contributors who have taken time to write up their lectures amidst their busy schedule. We regret we could not get the contributions of a few plenary speakers. We would also like to thank the members of Organizing Committees who have worked hard to make this conference a success.

In June of 1996, at the idyllic seaside resort of Guaruja, Brazil, a renowned group of researchers in space and astrophysical plasmas met to provide a forum on Advanced Topics on Astrophysical and Space Plasmas at a school consisting of some 60 students and teachers, mainly from Brazil and Argentina, but also from all the other parts of the globe. The purpose was to provide an update on the latest theories, observations, and simulations of space-astrophysical plasma phenomena. The topics covered included space plasma mechanisms for particle acceleration, nonthermal emission in cosmic plasma, magnetohydrodynamic instabilities in solar, interstellar, and other cosmic objects, magnetic field line reconnection and merging, the nonlinear and often chaotic structure of astrophysical plasmas, and the advances in high performance supercomputing resources to replicate the observed phenomena. The lectures were presented by Professor Mark Birkinshaw of the Harvard-Smithsonian Center for Astrophysics and the University of Bristol; Dr Anthony Peratt, Los Alamos National Laboratory Scientific Advisor to the United States Department of Energy; Dr Dieter Biskamp of the Max Planck Institute for Plasma Physics, Garching, Germany; Professor Donald Melrose, Director, Centre for Theoretical Astrophysics, University of Sydney, Australia; Professor Abraham Chian of the National Institute for Space Research, Brazil; and Professor Nelson Fiedler-Ferrara of the University of Sao Paulo, Brazil. As summarized by Professor Reuven Opher, Institute of Astronomy and Geophysics, University of Sao Paulo, the advanced or interested student of space and astrophysical plasmas will find reference to nearly all modern aspects in the field of Plasma Astrophysics and Cosmology in the presented lectures.

This book is an updated and modified translation of the Russian edition of 1984. In the present edition, certain sections have been abridged (in particular, Sects. 6.1 and 8.3) and the bibliography has been expanded. There are more detailed discus sions of the group properties of integrable systems of equations of mathematical physics (Sect. 3.4) and of the Riemannian problem in the context of the infinite dimensional internal symmetry groups of these systems of equations. There is an extended discussion of the reasons for the acceleration and retardation of pulsars in connection with more recent achievements of X-ray astronomy. Part of the material of Chap. 8 of the Russian edition has been included in Chap. 7; thus the number of chapters has been reduced to seven. S. Chandrasekhar set for me an example of brilliant analytical penetration into the essence of physical problems, and my book touches on his work in many in stances. The results of modem quantum theories of strong fields are not presented, but they can be found in the fundamental monographs Quantwn Electrodynamics of Strong Fields by W. Greiner, B. Muller, J. Rafelski (Sprioger-Verlag, Berlin, Heidelberg, New York 1985) and Quantwn Effects in Intense External Fields in Russian] by A. Grib, S. Mamaev, W. Mostepanenko (Energoatomizdat, Moscow 1988). This book was translated by Dr. N. M. Queen; I am very grateful to him. I thank sincerely H. Latta, C.-D. Bachem, V. Rehman, S. von Kalckreuth for preparing of the english manuscript."

Space missions subject human beings or any other target of a spacecraft to a radiation environment of an intensity and composition not available on earth. Whereas for missions in low earth orbit (LEO), such as those using the Space Shuttle or Space Station scenario, radiation exposure guidelines have been developed and have been adopted by spacefaring agencies, for exploratory class missions that will take the space travellers outside the protective confines of the geomagnetic field sufficient guidelines for radiation protection are still outstanding. For a piloted Mars mission, the whole concept of radiation protection needs to be reconsidered. Since there is an increasing interest ci many nations and space agencies in establishing a lunar base and lor exploring Mars by manned missions, it is both, timely and important to develop appropriate risk estimates and radiation protection guidelines which will have an influence on the design and structure of space vehicles and habitation areas of the extraterrestrial settlements. This book is the result of a multidisciplinary effort to assess the state of art in our knowledge on the radiation situation during deep space missions and on the impact of this complex radiation environment on the space traveller. ]t comprises the lectures by the faculty members as well as short contributions by the students given at the NATO Advanced Study Institute "Biological Effects and Physics of Solar and Galactic Cosmic Radiation" held in Armacao de Pera, Portugal, 12-23 October, 1991.

The basic subjects and main topics covered by this book are: (1) Physics of Black Holes (classical and quantum); (2) Thermodynamics, entropy and internal dynamics; (3) Creation of particles and evaporation; (4) Mini black holes; (5) Quantum mechanics of black holes in curved spacetime; (6) The role of spin and torsion in the black hole physics; (7) Equilibrium geometry and membrane paradigm; (8) Black hole in string and superstring theory; (9) Strings, quantum gravity and black holes; (10) The problem of singularity; (11) Astrophysics of black holes; (12) Observational evidence of black holes. The book reveals the deep connection between gravitational, quantum and statistical physics and also the importance of black hole behaviour in the very early universe. An important new point discussed concerns the introduction of spin in the physics of black holes, showing its central role when correctly put into the Einstein equations through the geometric concept of torsion, with the new concept of a time-temperature uncertainty relation, minimal time, minimal entropy, quantization of entropy and the connection of black hole with wormholes. Besides theoretical aspects, the reader will also find observational evidence for black holes in active galactic nuclei, in binary X-ray sources and in supernova remnants. The book will thus interest physicists, astronomers, and astrophysicists at different levels of their career who specialize in classical properties, quantum processes, statistical thermodynamics, numerical collapse, observational evidence, general relativity and other related problems.

th The 29 International Conference was held as the first one of the millennium at its Fort Lauderdale venue. These conferences began, with High Energy Physics being the main topic, by introducing gradually cosmology into its programs. These proceedings of the 2000 conference reflect the variety of topics and ideas discussed. Our future conferences will be designed somewhat akin to the early Coral Gables Conferences where we shall seek some convergence of ideas. For this reason various committees have been formed from among the participating physicists. The committees and their memberships are listed in these proceedings. We further decided for the first time to include some graduate student participants in our future meetings for which also a committee has already been established. The topics will demonstrate a more activist structure of the Coral Gables Conferences, for example the duality of the gravitational forces and expansion of the universe will be discussed from this point of view since it conveys a convergence to the ideas of quintessence versus the ordinary theory, which are considered as the cause of the expansion of the universe. We further wish to announce that the future conferences will assume a collective organization where several committees as listed in these proceedings will have their input into the conference. We have now introduced new topics and ideas, which referred especially to the attractive and repulsive nature of the gravitational force. These proceedings of the conference contain a variety of topics and ideas.

This volume consists of invited talks and contributed papers presented at the NATO Advanced Study Institute "The Post Recombination Universe" which was held in Cambridge in the summer of 1987. There have, in recent years, been numerous meetings devoted to problems in observational cosmology. The attention given reflects the exciting rate of de velopment of the subject, and a survey of the proceedings from these symposia reveals that a great deal of emphasis has been given to consideration of the very early universe on the one hand, and to large scale structure in the universe at the present epoch on the other. The theme of this meeting was chosen to comple ment these efforts by focussing on the state of the universe at quite early times, but at those epochs which are still accessible to direct observations. The meet ing provided a broad coverage of the post recombination universe by drawing on experts from a wide variety of fields covering theory, background radiation fields and discrete sources at high redshift. Events in the moderately early universe will have left their mark in a great range of wavebands, from X-rays to the microwave region, and the evolution of the universe can be revealed by studies of the inter galactic medium, gravitational lensing and the abundance and clustering of high redshift sources. All of these subjects received much attention at the meeting, and the papers demonstrate the rich interplay between these areas in the rapidly expanding world of observational cosmology."

When my colleague Dr. Paul Kent asked me which branch of Physics was most lively and which would lend itself best to a small high quality Symposium, I had no hesitation in answering 'Cosmology'. It seemed very timely that a meeting should take place which would bring together scientists interested in all branches of Astronomy, including Cosmic Rays, and Elementary Particles too and endeavour to put at least some of the pieces of the jigsaw together. The vast majority of the papers presented were later produced ~n appropriate camera-ready form and are published in this volume. I am very grateful to the authors for their ready cooperation. Grateful thanks are also extended to the Board of Management of the Foster-Wills and Theodor Heuss Scholarships, Oxford University and the Deutscher Akademischer Austauschdienst (German Academic Exchange Service) who funded the Symposium. The Director of the German Academic Exchange Service, Frau M.E. Schmitz and her colleague Mrs. Susan Putt, organized the whole meeting in a most exemplary fashion. Finally, on behalf of all participants and guests, s~ncere thanks are offered to Paul Kent as Convenor for initiating the Symposium, arranging the social events and organizing accommodation in such magnificent surroundings. Christ Church was the horne of Lewis Carrol and we were ever mindful - and appropriately so - of Alice. A. W. Wolfendale Durham, February 10th, 1982 vii A. W. Wolfendale (ed.), Progress in Cosmology, vii.

This book is based upon the lectures delivered from 18 to 22 June 2007 at the INFN-LaboratoriNazionali di Frascati School on Attractor Mechanism, directed by Stefano Bellucci, with the participation of prestigious lecturers, including S. Ferrara, M. Gnaydin, P. Levay, T. Mohaupt, and A. Zichichi. All lectures were given at a pedagogical, introductory level, a feature which is re?ected in the s- ci?c "?avor" of this volume, which has also bene?ted much from the extensive discussions and related reworking of the various contributions. This is the fourth volume in a series of books on the general topics of sup- symmetry, supergravity, black holes, and the attractor mechanism. Indeed, based on previous meetings, three volumes have already been published: BELLUCCI S. (2006). Supersymmetric Mechanics - Vol. 1: Supersymmetry, NoncommutativityandMatrixModels.(vol.698, pp.1-229).ISBN:3-540-33313-4. Berlin, Heidelberg: Springer Verlag (Germany). Springer Lecture Notes in Physics Vol. 698. BELLUCCIS., S.FERRARA, A.MARRANI.(2006).SupersymmetricMech- ics - Vol. 2: The Attractor Mechanism and Space Time Singularities. (vol. 701, pp. 1-242). ISBN-13: 9783540341567. Berlin, Heidelberg: Springer Verlag (G- many). Springer Lecture Notes in Physics Vol. 701. BELLUCCIS.(2008).SupersymmetricMechanics-Vol.3: AttractorsandBlack HolesinSupersymmetricGravity.(vol.755, pp.1-373).ISBN-13:9783540795223. Berlin, Heidelberg: Springer Verlag (Germany). Springer Lecture Notes in Physics 755. In this volume, we have included two contributions originating from short p- sentations of recent original results given by participants, i.e., Wei Li and Filipe Moura.

Our current perspective has arisen over millennia, through falling apples, elevator thought experiments and stars spiralling into black holes; Free fall and self-force in general relativity.

In fact, we do not have in mind to make a 1:1 reflection of the school. The ordering has been rearranged to tie articles together more coherently. We also propose to ask authors to focus their contributions according to the title we have suggested and to give a more complete description of current and future directions. We expect this will add to the volume s value for all anticipated readers. This volume has the unique feature of presenting a multifaceted approach to mass, which is intended mainly for graduate students and young doctoral researchers in the field of gravitation, who might be hoping to find a concise and introductory presentation of advanced topics outside their research field.

It is true that research from the infinitesimal scale of particle physics to the cosmic scale of the universe is concerned with the mass. While there have been spectacular advances in physics during the past century, mass still remains as a mysterious entity at the forefront of current research. Particle accelerators in the quest for the Higgs boson, laser interferometers sensitive enough to respond to gravitational waves, equivalence principle tests and detectors for dark matter are among the most ambitious and expensive experiments that fundamental physics has ever envisaged, and strongly attest to this fact. Both the self-force and radiation reaction are, in fact, lively topics of research. Related to the nature of motion, they have been hotly debated within general relativity from the inception of the theory. Recent developments have shown that radiation reaction is unavoidable in determining the gravitational waveforms emitted from a source such as the capture of a solar mass star by super-massive black hole (EMRI).

The main theme of this volume is mass and its motion within general relativity (and other theories of gravity), particularly for compact bodies, to which many articles directly refer. Within this framework, there are chapters on post-Newtonian and related methods (Blanchet, Gourgoulhon and Jaramillo, Nagar, Schafer), as well as on the self-force approach to the analysis of motion (Barack, Detweiler, Gal tsov, Poisson, Wald, Whiting), summarised along with an historic development of the field (Spallicci) and a snapshot on the state of the art (Burko). Note that self-acceleration depends directly on the mass of the body experiencing it. Mass itself is essential for this effect on motion.

Auxiliary chapters set the context for these theoretical contributions within the wider context of experimental physics. The space mission LISA (Jennrich) has been designed to detect the gravitational waves from EMRI captures, while other LISA sources may have electromagnetic counterparts (van Putten). Motion in modern gravitation must confront alternative theories (Esposito-Farese) and it must to be comprehensible within a quantum context (Noui), and demands an account of the relation between vacuum fluctuations and inertia (Jaekel and Reynaud). A volume centred on the fundamental role of mass in physics should face issues related to the basic laws of mechanics proposed by Newton (Lammerzahl) and precision measurements (Davis).

The role of the Higgs boson within physics is to give a mass to elementary particles (Djouadi), by interacting with all particles required to have a mass and thereby inducing inertia.

Moreover, most mass in the universe is dark, and only indirectly detected. A proposed alternative to dark matter theories is due to a modified theory of gravity (Esposito-Farese) such as MOND (MOdified Newtonian Dynamics). Even if general relativity does not explain gravity, there still remains the fundamental problem of reconciling any theory of gravity with the physics of quantum fields (Noui), itself so well verified experimentally. "

P. de Bernardis, S. Masi , G. Moreno Dipartimento di Fisica, Universita' "La Sapienza" 00184 Roma Italy ABSTRACT. Anisotropy measurement techniques and results are reviewed, with special attention given to experimental problems. The cosmological relevance of the dipole anisotropy, the only anisotropy truly detected in the Cosmic Background Radiation, is discussed. 1. INTRODUCTION Anisotropy of the Cosmic Background Radiation at 2.7 K (CBR hereafter) is a cosmological topic with a wide range of applications. In order to define anisotropy let us consider fig. 1 a, where the celestial sphere is shown with two beams A and B, with beamwidth 0 and angular separation e. We define the anisotropy of CBR at angular scale e in terms of the difference i'2,1 between the CBR flux I(ex,u) measured in the two beams. At small angular scales (e ) a "stochastic" approach is preferred, and the anisotropy is defined as .cJ I = GBP (1) I e where the brackets indicate averages over the whole celestial sphere. At large angular scales e>l a deterministic approach is preferred, and the CBR flux I(ex, S) is expressed as a sum of spherical harmonics (2) I (ex, S) = I ~ aIm Y (ex, S) lm I,m The alm coefficients give the dipole, quadrupole and higher order components of the anisotropy. 257 P. Galeotti and D. N. Schramm (eds.), Gauge Theory and the Early Universe, 257-282.

Many large-scale projects for detecting gravitational radiation are currently being developed, all with the aim of opening a new window onto the observable Universe. As a result, numerical relativity has recently become a major field of research, and Elements of Numerical Relativity and Relativistic Hydrodynamics is a valuable primer for both graduate students and non-specialist researchers wishing to enter the field.

A revised and significantly enlarged edition of LNP 673 Elements of Numerical Relativity, this book starts with the most basic insights and aspects of numerical relativity before it develops coherent guidelines for the reliable and convenient selection of each of the following key aspects: evolution formalism; gauge, initial, and boundary conditions; and various numerical algorithms. And in addition to many revisions, it includes new, convenient damping terms for numerical implementations, a presentation of the recently-developed harmonic formalism, and an extensive, new chapter on matter space-times, containing a thorough introduction to relativistic hydrodynamics.

While proper reference is given to advanced applications requiring large computational resources, most tests and applications in this book can be performed on a standard PC.

The theory of General Relativity, after its invention by Albert Einstein, remained for many years a monument of mathemati cal speculation, striking in its ambition and its formal beauty, but quite separated from the main stream of modern Physics, which had centered, after the early twenties, on quantum mechanics and its applications. In the last ten or fifteen years, however, the situation has changed radically. First, a great deal of significant exper en tal data became available. Then important contributions were made to the incorporation of general relativity into the framework of quantum theory. Finally, in the last three years, exciting devel opments took place which have placed general relativity, and all the concepts behind it, at the center of our understanding of par ticle physics and quantum field theory. Firstly, this is due to the fact that general relativity is really the "original non-abe lian gauge theory," and that our description of quantum field in teractions makes extensive use of the concept of gauge invariance. Secondly, the ideas of supersymmetry have enabled theoreticians to combine gravity with other elementary particle interactions, and to construct what is perhaps the first approach to a more finite quantum theory of gravitation, which is known as super gravity."

Any student working with the celebrated Feynman Lectures will ?nd a chapter in it with the intriguing title Electromagnetic Mass [2, Chap. 28]. In a way, it looks rather out of date, and it would be easy to skate over it, or even just skip it. And yet all bound state particles we know of today have electromagnetic mass. It is just that we approach the question differently. Today we have multiplets of mesons or baryons, and we have colour symmetry, and broken ?avour symmetry, and we think about mass and energy through Hamiltonians. This book is an invitation to look at all these modern ideas with the help of an old light. Everything here is quite standard theory, in fact, classical electromagnetism for the main part. The reader would be expected to have encountered the theory of elec tromagnetism before, but there is a review of all the necessary results, and nothing sophisticated about the calculations. The reader could be any student of physics, or any physicist, but someone who would like to know more about inertia, and the clas sical precursor of mass renormalisation in quantum ?eld theory. In short, someone who feels it worthwhile to ask why F= ma.

This workshop was intended as an update and an extension of the workshop 011 the "Spectral Evolution of Galaxies" that was held in Erice two years ago. It concentrates 011 Ilew developments concerning galaxies seen at large look back times. This seemed also a good opportunity to look ahead to the next generation of ground- and space based instrumentation, and to consider various future strategies for collecting information concerning the edge of the observable universe. The main idea was to bring together people with specialities in modelling galaxy components (such as stars, clusters, gas, and dust) as well as whole stellar systems (stellar populations, star formation rates, chemical enrichment), and people specialized in making direct measurements of galaxies and clusters at large look back times. The confrontation of expectations and observations was planned to be the central theme of the conference, which explains the title "Towards Understanding Galaxies at Large Redshift." The first part of the workshop focussed on the physical processes that operate in galaxies, and that would likely have some observable manifestation at large redshifts. In the second part the most recent observational work was reported, and we were pleased to have the participation of most of the groups active in this field. The last part was directed towards new approaches to be made possible by the next generation of instrumentation, although in general all the contributions were indeed in this spirit of setting more ambitious goals."

This book evolved out of some one hundred lectures given by twenty experts at a special instructional conference sponsored by the University Grants Commis sion, India. It is pedagogical in style and self-contained in several interrelated areas of physics which have become extremely important in present-day theoretical research. The articles begin with an introduction to general relativity and cosmology as well as particle physics and quantum field theory. This is followed by reviews of the standard gauge models of high-energy physics, renormalization group and grand unified theories. The concluding parts of the book comprise discussions in current research topics such as problems of the early universe, quantum cosmology and the new directions towards a unification of gravitation with other forces. In addition, special concise treatments of mathematical topics of direct relevance are also included. The content of the book was carefully worked out for the mutual education of students and research workers in general relativity and particle physics. This ambitious programe consequently necessitated the involvement of a number of different authors. However, care has been taken to ensure that the material meshes into a unified, cogent and readable book. We hope that the book will serve to initiate and guide a student in these different areas of investigation starting from first principles and leading to the exciting current research problems of an interdisciplinary nature in the context of the origin and structure of the universe."

Scientists in the late twentieth century are not the first to view galaxy formation as a phenomenon worthy of explanation in terms of the known laws of physics. Already in 1754 Kant regarded the problem as essentially solved. In his Univerlal Natural Hutory and Theory 0/ the H eaven$ he wrote; "If in the immesurable space in which all the suns of the Milky Way have formed themselves, we assume a point around which, through some cause or other, the first formation of nature out of chaoo began, there the largest mass and a body of extraordinary attraction will have arisen which has thereby become capable of compelling all the systems in the process of being formed within an enormous sphere around it, to fall towards itself as their centre, and to build up a system around it on the great scale . . . . Observation puts this conjecture almost beyond doubt. " More than 200 years later, a similar note of confidence was voiced by Zel'dovicb at an IAU symposium held in Tallin in 1911; "Extrapolating . . . to the next symposium somewhere in the early eighties one can be pretty sure that the question of the formation of galaxies and clusters will be solved in the next few years. " Perhaps few astronomers today would share Kant's near certainty or feel that Zel'dovich's prophecy has been fulfilled, Many, however, will sympathize with the optimistic olltlook of these two statements.