This volume is a collection of experimental and theoretical papers presented at the international "Topical Meeting on Optical Bistability," held at the University of Rochester, June 15-17, 1983, sponsored jointly by the Air Force Office of Scientific Re search; the Army Research Office; and the Optical Society of America. The Conference, which had 150 attendees, overlapped (on June 15) with the Fifth Rochester Conference on Coherence and Quantum Optics with two joint sessions. Some of the topics cover ed in this volume are also treated io the Proceedings of that Conference. Since the last international conference on Optical Bistability, held in Asheville, North Carolina, June 3-5, 1980, there have been new and important fundamental advances in the field. This is borne out in papers in this volume dealing with optical chaos and period doubling bifurcations leading to chaos as well as the report of results of an experiment using a very simple system exhibiting ab sorptive optical bistability in a ring cavity using optically pump ed sodium atoms, which was successfully analyzed quantitatively by a simple theory. Other advances discussed here include the ob servation of optical bistability due to the effect of radiation pressure on one mirror of a fabry-Perot cavity. and the prediction of mirrorless intrinsic opittal bistability due to the local field correction incorporated into the Maxwell-Bloch formulation. Advances in optical bistability in semiconductors relate closer to actual device applications."

This book deals with the fundamentals of stellar interferometry with emphasis on aperture synthesis using sparse array of telescopes particularly at optical/IR wavelengths, the origin, properties, and optical effects of turbulence in the Earth's atmosphere, techniques developed to overcome image degradation. Studded with more than one hundred and fifty illustrations and tens of footnotes, it addresses the basic tricks of trade, current trend, motivation, methods, and path to future promise of true interferometry both from the ground and space. Also discussed are the technical challenge involved, such as beam transportation and recombination, detecting fringes using modern sensors, and image synthesis. Astronomical science that benefits from aperture synthesis imaging are highlighted as well.

Light scattering and absorption by small homogeneous particles can be worked-out exactly for spheres and infinite cylinders. Homogeneous particles of irregular shapes, when averaged with respect to rotation, have effects that can in general be well-approximated by reference to results for these two idealised cases. Likewise, small inhomogeneous particles have effects similar to homogeneous particles of the same average refractive index. Thus most problems can be solved to a satisfactory approximation by reference to the exact solutions for spheres and cylinders, which are fully stated here in the early part of the book. The sum of scattering and absorption, the extinction, is too large to be explained by inorganic materials, provided element abundances in the interstellar medium are not appreciably greater than solar, H 0 and NH3 being essentially excluded in the 2 general medium, otherwise very strong absorptions near 3p, m would be observed which they are not. A well-marked extinction maximum in the ultraviolet near 2200A has also not been explained satisfactorily by inorganic materials. Accurately formed graphite spheres with radii close to O.02p, m could conceivably provide an explanation of this ultraviolet feature but no convincing laboratory preparation of such spheres has ever been achieve

These proceedings are the result of a three-day meeting held in Oogliani (Italy), on October 2-4 2003, whose title was "VIrtual Astrophysical Jets 2003". Our goal in convening this meeting was to gather some of the scientists among the most active in the field of numerical simulations and modelling of astrophysi cal jets. For keeping the participants close to the "real world", we also invited a few observers to give up-to-date reviews outlining the state-of-the-art of jet observations. The principal aim of the meeting was thus to present and critically discuss the state-of-the-art numerical simulations, analytical models and laboratory ex periments for reproducing the main aspects of astrophysical jets and compar ing them with observations. The discussion has been focused on the following topics: * Observations and intepretions of jets from young stars and AGNs, comparisons of models with observations; * MHO accelerations of jets: steady self-similar models, MHO numerical simula tions of time-dependent accelerations mechanisms; * Jet stability and interaction with the ambient: formation of knots in YSO jets, jet survival to instabilities, deceleration of relativistic jets in FRI sources, simulations of jets-IGM interactions, jets propagation and galaxy formation; * Numerical codes and their validation: relativistic MHO codes, comparisons among different numerical schemes, jets in the laboratory and code validation. These topics have been discussed intensively during the meeting, and the out come of these discussions is presented in this volume. The contributions have been divided in five sections.

The General Assemblies of the International Astronomical Union are landmarks in the life of the world-wide astronomical community, as they review, at triennial intervals, the progress made in this scientific field, promulgate the most spect acular astronomical achievements, formulate scientific programmes for the years to come and, last but not least, deal with the administration and finances of the IAU. The Reports on Astronomy 1976, published as Transactions XVIA (in 3 volumes) before the XVlth General Assembly, are a synopsis of the work done in astronomy from 1973 to 1975. The volume "Highlights of Astronomy, as presented at the XVlth General As sembly of the IAU in Grenoble, 1976" includes some selected scientific topics, and will appear in the first half of 1977. Apart from the Invited Discourses and the Proceedings of the seven Joint Discussions, the Highlights volume No.4 con tairsthe proceedings of two Joint Commissions Meetings."

IAU Transactions are published as a volume corresponding to each General Assembly. Volume A is produced prior to the Assembly and contains Reports on Astronomy, prepared by each Commission President. The intention is to summarize the astronomical results that have affected the work of the Commission since the production of the previous Reports up to a time which is about one year prior to the General Assembly. Volume B is produced after the Assembly and contains accounts of Commission Meetings which were held, together with other material. The reports included in the present volume range from outline summaries to lengthy compilations and references. Most reports are in English.

The 2nd International Conference on Space Engineering took place May 7-10, 1969, at Venice, Italy, under the organization of the Centro Studi Trasporti Missilistici and the Association pour l'Etude et la Recherche Astronautique et Cosmique. Its purpose was to bring together those interested in the technological development of space components, to exchange information by the presentation of papers and to discuss present problems and future trends, and to this end forty-eight papers were presented by distinguished experts from all over the world. The papers were selected from as wide a background as possible, approximately an equal number coming from the academic and research establishments as from industry. The principal criterion for their selection was that they should contribute to the knowledge of Space Engineering, and have application either to the improve ment of current technologies or to the design of more advanced systems for the future. Six pertinent sessions were planned which covered the major areas of interest: (1) Structures and Materials, where three important papers were presented; (2) Guidance and Control Systems, in which six valuable papers were presented, in cluding problems of controlling space ships, details of the inertial guidance system of the ELDO launch vehicle, the attitude control system of the "Europa 2"; (3) Propellants and Combustion, where eleven papers described recent work on solid and liquid rocket engines, advanced fuels and oxidizers, effects of additives, propellant injection, propellant expulsion techniques; (4) Propulsion, in which session ten papers"

decision and investigative process of the scientist, they can also wri te the paragra}ils of scientific resul ts. Once a canputer research activity progresses from intuitive guesses to a systematic study, the canputer program can free the scientist to pursue new original ideas. '!his concept is illustrated in the ptper by Hut. Sussnan says "Knowledge" is knowing what not to canpute. His main message is that we must change from trying to maximize the efficiency of the canputer to maximizing the effectiveness of the scientist. The canputer is relatively cheap, it is the trained scientist who is most valuable. In the second keynote address, R. L. Duncombe (University of Texas) described the "Early Applications of Canputer Technology to Dynamical Astronany. " His talk traced the worldwide introduction of punched card equipnent and their applications through the use of the first electronic canputers. Sussman and Duncombe, therefore, provided a forecast and review of the use of computers in dynamical astronany. This proceedings is intended to provide a consolidated general view of the ptst, present, and future of the Applications of Canputer Technology to Dynamical Astronany. Of necessity this requires that the ptpers be rela ti vely short and provide references to the more canplete discussions. Thanks to the representa tion from so many different countries the proceedings give a picture of the activities worldwide. The Scientific Organizing Comnittee included K. B. IIlatnagar, V. A. Brtmberg, G. Contopoulos, A. Depri t , J. Henrard, J. Kovalevsky, Y.

In their approach to Earth dynamics the authors consider the fundamentals of "Jacobi Dynamics" (1987, Reidel) for two reasons. First, because satellite observations have proved that the Earth does not stay in hydrostatic equilibrium, which is the physical basis of today's treatment of geodynamics. And secondly, because satellite data have revealed a relationship between gravitational moments and the potential of the Earth's outer force field (potential energy), which is the basis of "Jacobi Dynamics." This has also enabled the authors to come back to the derivation of the classical virial theorem and, after introducing the volumetric forces and moments, to obtain a generalized virial theorem in the form of Jacobi's equation. Thus a physical explanation and rigorous solution was found for the famous Jacobi's equation, where the measure of the matter interaction is the energy.
The main dynamical effects which become understandable by that solution can be summarized as follows:
" "the kinetic energy of oscillation of the interacting particles which explains the physical meaning and nature of the gravitation forces;
" "separation of the shell's rotation of a self-gravitating body with respect to the mass density;
difference in angular velocities of the shell rotation;
" "continuity in changing the potential of the outer gravitational force field together withchanges in density distributionof the interacting masses (volumetric center of masses);
" "the nature of the precession of the Earth, the Moon and satellites; the nature of the rotating body's magnetic field and the generation of the planet's electromagnetic field.As a final result, the creation of the bodies in the Solar System having different orbits was discussed. This result is based on the discovery that all the averaged orbital velocities of the bodies in the Solar System and the Sun itself are equal to the first cosmic velocities of their proto-parents during the evolution of their redistributed mass density.
Audience
The work is a logical continuation of the book "Jacobi Dynamics" and is intended for researchers, teachers and students engaged in theoretical and experimental research in various branches of astronomy (astrophysics, celestial mechanics and stellar dynamics and radiophysics), geophysics (physics and dynamics of the Earth's body, atmosphere and oceans), planetology and cosmogony, and for students of celestial, statistical, quantum and relativistic mechanics and hydrodynamics.

The second workshop on High Energy Astrophysics of the Ma..x-Planck-Society and the Academia Sinica was held at Ringberg Castle near Tegernsee during the week July 12-July 17, 1987. It is the purpose of these workshops to en courage the exchange of ideas between German and Chinese astrophysicists (scientists from other countries are also welcome, of course), and the pleas ant atmosphere and surroundings of Ringberg Castle certainly helped the development of relaxed and stimulating discussions. In addition, we seemed to have picked out the one week of perfect weather during a rainy summer. Thanks are due to Mr. Hormann and his staff for creating a perfect infra structure. The proceedings have required a considerable amount of editing, and I hope that all the papers are comprehensible. Thanks are due to Miss Petra Berkemeyer and Miss Hannelore Muller, who patiently retyped several manu scripts and helped with other editing jobs. I did not feel that a sharp refer eeing procedure should be done, although I do not agree with all the papers in this volume. The interested reader will find that this book gives a fair account of the present status of Chinese activities in the field of high energy astrophysics, i.e. in supernova physics, accretion onto compact objects, active galaxies, and cosmology."

In the 18th century, purely scientific interests as well as the practical necessities of navigation motivated the development of new theories and techniques to accurately describe celestial and lunar motion. "Between Theory and Observations" presents a detailed and accurate account, not to be found elsewhere in the literature, of Tobias Mayer's important contributions to the study of lunar motion-including the creation of his famous set of lunar tables, which were the most accurate of their time.

Optics is reborn. There is fresh new vitality in applying old techniques to new prob lems and fully exploring novel phenomena. Lasers, holography, stellar navigation, nonlinear phenomena, and remote sensing are subjects of the seventies, and their further development will increase our understanding of nature and the development of technology. This Series is devoted to provid ing ideas and data to nourish the growth of these scientific and engineering en deavors' for we feel strongly that science and engineering flourish best when they grow together. Some of the volumes in the Series will be devoted to the optical properties of materials, theories of the detailed mechanisms of absorption, reflection, and nonlinea r phenomena, and electro-optical coefficients. The understanding of such things leads to further engineering applications. Companions to such theoretical books will be compendia of property data; the triad is completed by monographs on the use of the materials in op tical and electro-optical systems. Laser materials, lasers, and laser sys tems form one of the groups which will comprise the full set of ready-reference material for the entire field. The Series will be intentionally international, including a fair sampling of Russian work. There are important benefits to be obtained in the alternate approaches often taken by our Soviet and other foreign colleagues (just as they can gain from studying ours)."

The Cargese Workshop Random Surfaces and Quantum Gravity was held from May 27 to June 2, 1990. Little was known about string theory in the non-perturbative regime before Oetober 1989 when non-perturbative equations for the string partition functions were found by using methods based on the random triangulations of surfaees. This set of methods pro vides a deseription of non-eritical string theory or equivalently of the coupling of matter fields to quantum gravity in two dimensions. The Cargese meeting was very successful in that it provided the first opportunity to gather most of the active workers in the field for a fuH week of lectures and extensive informal discussions about these exeiting new developments. The main results were reviewed, recent advances were explained, new results and conjectures (which appear for the first time in these proceedings) were presented and discussed. Among the most important topics discussed at the workshop were: The relation of KdV theory to loop equations and the Virasoro algebra, new results in Liouville field theory, effective (1 + 1) dimensional theory for 2 - D quantum gravity coupled to c = 1 matter and its fermionization, proposal for a new geometrical interpretation of the string equation and possible definition of quantum Riemann surfaces, discussion of the string equation for the multi-matrix models, links with topological field theories of gravity, issues in using target space supersymmetry to define good theories, definition of the partition function via analytic continuation, new models of random surfaces

Modern astronomical research faces a vast range of statistical issues which have spawned a revival in methodological activity among astronomers. The Statistical Challenges in Modern Astronomy II conference brought astronomers and statisticians together to discuss methodological issues of common interest. Time series analysis, image analysis, Bayesian methods, Poisson processes, nonlinear regression, maximum likelihood, multivariate classification, and wavelet and multiscale analyses were all important themes. Many problems were introduced at the conference in the context of large-scale astronomical projects including LIGO, AXAF, XTE, Hipparcos, and digitised sky surveys. As such, this volume will be of interest to researchers and advanced students in both fields - astronomers seeking exposure to recent developments in statistics, and statisticians interested in confronting new problems.

The launch in October 1990 of the joint ESA-NASA Ulysses mission marked the start of a new era in the study of the heliosphere. For the fIrst time, in-situ observations are being made covering the full range of heliographic latitudes. Following the successful gravity-assist manoeuvre at Jupiter in February 1992, Ulysses left the ecliptic plane in a southerly direction and headed back toward the Sun, passing over the southern solar pole in mid-1994. To mark these unique events, the 28th ESLAB Symposium, held in Friedrichs hafen, Germany, on 19-21 April 1994, was devoted to "The High Latitude Helio sphere." Following on from the highly successful 19th ESLAB Symposium "The Sun and the Heliosphere in Three Dimensions" (Les Diablerets, 1985), the purpose of the meeting was to review out-of-ecliptic results from the Ulysses mission obtained to date, and to provide a focus for the fIrst polar pass. Relevant results from other space missions, as well as ground-based and theoretical studies, were also included. Attended by 130 scientists, the main themes of the Symposium were The Sun and Corona, Large-Scale Heliospheric Structure, Energetic Particles in the Heliosphere, Cosmic Rays in the Heliosphere, and Interstellar Gas and Cosmic Dust. The scientifIc programme consisted of a number of Topical Review papers introducing various as pects of these themes, supplemented by a large number of contributed papers (72 in to tal) presented either orally or as posters. Undoubtedly, the excellent poster sessions formed one of the highlights of the meeting."

An almost complete collection of the papers given at the International Workshop on Imaging in High Energy Astronomy (Anacapri, Italy, 1994). These proceedings, which concentrate on imaging above 10 keV, represent the state of the art in the field, resulting from the success of many missions (I.C. Granat and CGRO) carrying detectors for high energy astronomy with imaging capabilities. The main topics of the book are Bragg concentrators, coded mask-modulation collimators, double Compton telescopes, the occultation method, tracking chambers, and new experimental techniques. The book also contains some papers dealing with image reconstruction and processing, with an emphasis on the above techniques.

Our Galactic center's proximity allows astronomers to study physical pro cesses within galactic nuclei at a level of detail that will never be possible in the more distant, but usually also more spectacular, extragalactic systems. Recent advances in instrumentation from the radio, through the submillime ter and infrared wavebands, and out to the X- and "'(-ray bands now allow observations of the Galactic Center over thirteen orders of magnitude in wave length. Our knowledge about the central few hundred parsecs of our Galaxy has consequently increased vastly over the past decade. The same new instru ments provide high resolution, high quality measurements of nearby ''normal'' galactic nuclei; that is, nuclei whose modest energy output is comparable to that of our own (and most other) galaxies. Theorists, spurred in part by the new observations, have been able to refine models of the energetics, dynam ics, and evolution of the gas and stellar systems deep within galactic nuclei."

Modern observations, including recent ones with the Hubble Space Telescope, have revealed that the Universe is replete with plasma outflows from all kinds of objects, ranging from stars in all their variety to galaxies. In this masterly survey of plasma astrophysics, written by leading practitioners, the first 15 articles in Part I deal with the use of the MHD approach in several key problems of solar plasma, such as magnetoconvection and magnetic field generation, sunspots and coronal loops, magnetic nonequilibrium and coronal heating, coronal mass ejections, the acceleration of the solar wind, and stellar winds across the Main Sequence. The following 16 articles of Part II deal with the use of the same MHD approach in several central and puzzling aspects of more distant astrophysical plasmas, such as the dynamics of the interstellar medium, collimated outflows from young stellar objects and accretion disks, molecular outflows and jets associated with enigmatic binaries and symbiotic stars, relativistic flows associated with superluminal microquasars in our own galaxy, astrophysical jets from nearby galaxies, or remote active galactic nuclei and quasars, probably fuelled by supermassive black holes. The emphasis throughout is on the striking underlying similarities in the physics of all these problems. Audience: Indispensable for solar physicists and astrophysics alike. An ideal textbook for graduate students in physics and astrophysics.

This volume is based on the proceedings of the "NATO Advanced study Institute on Mineral Processing Design" held in Bursa-Turkey on August 24-31, 1984. The institute was organized by Professor B. Yarar of the Colorado School of Mines, Golden, Colorado, 80401, USA, Professor G. Ozbayoghu and Professor Z. M. Dogan of METU-Ankara, Turkey, who was the director. The purpose of the institute was to provide an international forum on the subject and update the information available. Participants were from Turkey, England, Greece, Spain, Portugal, Belgium, Canada, and the USA. Besides authors contributing to this volume, presentations were also made by Drs. Yarar, Raghavan, Schurger, and Mr. Kelland. Many assistants and colleagues helped. They are gratefully acknowledged. Acknowledgment is also owed to Drs. Ek, de Kuyper, and Tolun. Dr. Gfilhan Ozbayoglu, and Mr. S. Ozbayoglu were particularly helpful in the overall organization and hosting of many international guests. We owe them special thanks. NATO, Scientific Affairs Division, is gratefully acknowledged for the grant which made this activity possible. Z. M. Dogan B. Yarar 2 APPLIED MINERALOGY IN ORE DRESSING William Petruk CANMET, 555 Booth Street, Ottawa, Ontario, KIA OGI ABSTRACT Mineralogy applied to ore dressing is a reliable guide for designing and operating an efficient concentrator. A procedure for conductiqg mineralogical studies in conjunction with ore dressing was, therefore, developed. The procedure includes characterizing the ore and analysing the mill products.

This book contains the lectures presented at the Summer Advanced Study School, 'Magnetospheric Particles and Fields' which was held at Graz, Austria during the period August 4-15, 1975. One hundred and one persons from fifteen different countries attended the Schoo . The authors and publisher have made a special effort for rapid publication of an up-to date status of particles, fields, and processes in planetary magnetospheres. Special thanks are due to the lecturers for their diligent preparation and excellent presentations. The in dividuallectures and the published papers were deliberately limited; the authors' cooper ation in conforming to these specifications is greatly appreciated. Many thanks are due to Drs C. D. Anger, Gerhard Haerendel, George P. Haskell, Carl McIlwain, Vytenis Vasy liunas, Martin Walt, and James Warwick who served as session chairmen during the School and contributed greatly to its success by skillfully directing the discussion period in a stimulating manner after each lecture. Many persons contributed to the success of the School. Drs C. D. Anger, Carl-Gunne Falthammar, Gerhard Haerendel, George P. Haskell, Carl McIlwain, David Nunn, Willi Riedler, Finn Scentsraas, Vytenis M. Vasyliunas, Martin Walt, and James Warwick were especially helpful in preparing the technical program. Dr Willi Riedler assisted in ar ranging for the facilities in Graz. Drs Gerhard Kremser and Martin Friedrich were most helpful with many aspects of the local arrangements in Graz. The assistant editor, Mrs Diana R. McCormac, checked the manuscripts and proofs, and worked hard to achieve a uniform style in this book."

Photobiology - the science of light and life - begins with basic principles and the physics of light and continues with general photobiological research methods, such as generation of light, measurement of light, and action spectroscopy. In an interdisciplinary way, it then treats how organisms tune their pigments and structures to the wavelength components of light, and how light is registered by organisms. Then follow various examples of photobiological phenomena: the design of the compound eye in relation to the properties of light, phototoxicity, photobiology of the human skin and of vitamin D, photomorphogenesis, photoperiodism, the setting of the biological clock by light, and bioluminescence. A final chapter is devoted to teaching experiments and demonstrations in photobiology.
This book encompasses topics from a diverse array of traditional disciplines: physics, biochemistry, medicine, zoology, botany, microbiology, etc., and makes different aspects of photobiology accessible to experts in all these areas as well as to the novice. It is intended primarily for graduate students and for researchers who wish to look outside their speciality, but can also act as a source of information for undergraduate students.

The European Workshop on White Dwarfs was initiated by Prof. V. Weidemann, with the first meeting held in Kiel (FRG) in 1974. Since then a similar workshop has been held almost every two years: Frascati (1976), Tel Aviv (1978), Paris (1981), Kiel (1984), Frascati (1986) and Toulouse (1990). Two major IAU colloquia have also been devoted to the study of white dwarfs (No. 53, Rochester NY, 1979; No. 114, Hanover, NH, 1988). Our most recent meeting, the 8th Workshop, marks a number of important advances in both observational and theoretical studies of white dwarfs. This coincides with a significant expansion in the size of the community active in the field, as was clear from an increase in the number of participants between this workshop (77) and that in Toulouse (46), just two years ago. Key parts of any workshop are the discussion sessions following the pa pers. However, these are difficult to record and, very often, the 'live' flavour of the debates is lost. During this workshop we carried out an experiment, recording the discussion sessions on video tape and then transcribing these later for the proceedings. Although the recordings were made in non-studio conditions with regard to lighting and noise, only a very small part was unin telligible. All participants were given an opportunity to check their questions and answers for scientific accuracy and to correct any errors arising in the transcription process."

In many areas of physics, such as astrophysics, solid-state physics, nuclear physics and particle physics, a major outstanding problem is a better understanding of corre lation phenomena. While in most cases the average properties of a system are rather well understood, the correlations and the resulting clustering are poorly understood. They are reflections of the force mediating the interaction among the constituents and play essential roles in determining the structure of a physical system. At the largest scales, in astrophysics, it has recently been realized that there are huge voids in space and almost all matter is concentrated on filaments, raising interesting questions concerning the origin of this clustering of matter. In nuclear physics corre lation phenomena are important in all its subfields. It has been realized that so-called fluctuations in the one-particle density, which are a manifestation of nucleon-nucleon correlations, are crucial. These are important for an understanding of heavy-ion reac tions. This is the subject of modern quantum transport theories. Correlations are also crucial in the description of the high momentum components as observed in quasi-elastic knock-out reactions."

The 25'" Coral Gables Conference was the culmination of the series that was begun in 1964. The conferences evolved under the titles that in~lude: Symmetry Principles at High Energy; Fundamental Interactions; Orbis Scientiae; and, occasionally, Unified Symmetry in the Small and in the Large. There was a pause after the 2()1h meeting in 1983 which was dedicated to P. A. M. Dirac. The conferences were resumed in 1993. Some of the reminiscences involved the absence of great minds who attended these meetings in the past and who were no longer with us. The list includes, just to name a few: Julian Schwinger, Robert Oppenheimer, Lars Onsager, Robert Hofstater, Abdus Salam, Richard Feynman, Stanislov Ulam, P. A. M. Dirac, Lord C. P. Snow, Eugene P. Wigner, Vladimir K. Zworykin, and Dixie Lee Ray. Most of these people were among the architects of modern physics and had participated in many of the early Coral Gables Conferences. We miss them. These conferences have contributed to the progress in high energy physics and cosmology. This year, again, papers were presented on familiar topics, such as neutrino masses, age and total mass of the universe, on the nature of dark matter, and on supersymmetry. The latter has now become a perennial issue. Like the weather, we all talk about it, but, so far cannot do anything to affect it. Another favorite subject was so-called monopoles, which theoretically participate in phenomena like condensation, confinement of electric charge, confinement of monopoles themselves, etc.

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.