In the book are reported the main results presented at the Third International Workshop on Data Analysis in Astronomy, held at the EUore Majorana Center for Scientific Culture, Erice, Sicily, Italy, on June 20-27,1988. The Workshop was the natural evolution of the two previous ones. The main goal of the first edition (Erice 1984) was to start a scientific interaction between Astronomers and Computer Scientists. Aim of the second (Erice 1986) was to look at the progress in data analysis methods and dedicated hardware technology. Data analysis problems become harder whenever the data are poor in statistics or the signal is weak and embedded in structured background. Experiments collecting data of such a nature require new and non-standard methodologies. Possibilistic approaches could be merged with the statistical ones, in order to formalize all the knowledge used by the scientists to reach conclusions. Moreover, the last decade has been characterized by very fast developments of Intelligent Systems for data analysis (knowledge based systems, ... ) that would be useful to support astronomers in complex decision making. For these reasons, the last edition of the workshop was intended to provide an overview on the state of the art in the data analysis methodologies and tools in the new frontieres of the astrophysics (y-astronomy, neutrino astronomy, gravitational waves, background radiation and extreme cosmic ray energy spectrum). The book is organized in two sections: - Data analysis methods and tools, - New frontieres in astronomy.

This book is a collection of essays written by the very scientists and engineers who have led, and continue to lead, the scientific quest known as SETI, the search for extraterrestrial intelligence. Divided into three parts, the first section, 'The Spirit of SETI Past', written by the surviving pioneers of this then emerging discipline, reviews the major projects undertaken during the first 50 years of SETI science and the results of that research. In the second section, 'The Spirit of SETI Present', the present-day science and technology is discussed in detail, providing the technical background to contemporary SETI instruments, experiments, and analytical techniques, including the processing of the received signals to extract potential alien communications. In the third and final section, 'The Spirit of SETI Future', the book looks ahead to the possible directions that SETI will take in the next 50 years, addressing such important topics as interstellar message construction, the risks and assumptions of interstellar communications, when we might make contact, what aliens might look like and what is likely to happen in the aftermath of such a contact.

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.

Laser physics and nonlinear optics are fields which have been intimately con nected from their beginning. Nonlinear optical effects such as second-har monic generation fulfil vital functions in many laser systems. Conversely advances in laser development quickly lead to progress in nonlinear optics. Of particular importance has been the development of tunable visible and uv lasers. With the ability to tune the laser frequency into close resonance with atomic transition frequencies, one can produce a large resonance en hancement of the nonlinearity. This permits the observation of a great var iety of nonlinear optical processes in dilute media such as atomic vapours. In recent years much of the research effort in nonlinear optics has been directed towards the use of such media, and it is this area which forms the subject of the present book. We review a wide range of nonlinear optical processes in atomic vapours, molecular gases and cryogenic liquids. At the same time we have tried to treat the subject in sufficient depth to be useful to research workers in the field. To achieve this, a measure of selectivity has been introduced by emphasising those nonlinear processes which are seen to have applications as sources of tunable coherent radiation. Thus we have not discussed in any detail those nonlinear processes whose main applications are in spec troscopy, such as Doppler-free two-photon absorption."

Although recent works on Galileo's trial have reached new heights of erudition, documentation, and sophistication, they often exhibit inflated complexities, neglect 400 years of historiography, or make little effort to learn from Galileo. This book strives to avoid such lacunae by judiciously comparing and contrasting the two Galileo affairs, that is, the original controversy over the earth's motion ending with his condemnation by the Inquisition in 1633, and the subsequent controversy over the rightness of that condemnation continuing to our day. The book argues that the Copernican Revolution required that the hypothesis of the earth's motion be not only constructively supported with new reasons and evidence, but also critically defended from numerous old and new objections. This defense in turn required not only the destructive refutation, but also the appreciative understanding of those objections in all their strength. A major Galilean accomplishment was to elaborate such a reasoned, critical, and fair-minded defense of Copernicanism. Galileo's trial can be interpreted as a series of ecclesiastic attempts to stop him from so defending Copernicus. And an essential thread of the subsequent controversy has been the emergence of many arguments claiming that his condemnation was right, as well as defenses of Galileo from such criticisms. The book's particular yet overarching thesis is that today the proper defense of Galileo can and should have the reasoned, critical, and fair-minded character which his own defense of Copernicus had.

These words are written on the SOOth anniversary of Columbus' discovery of the New World. Surely the deep-space exploration of other worlds in our Solar System over the past few decades is an event of similar magnitude. Man has traveled far enough to see Spaceship Earth suspended alone in black space. And he has voyaged even farther to marvel at the crescent Earth rising over the Moon's cratered terrain. Instrumented spacecraft have toured the entire Solar System even beyond the ninth planet Pluto. This work of science Morphology of the Rocky Members of the Solar System is an inquiry about our extended home. As with the Darwinian and Copernican paradigms, the nature of our planetary system, as the extended world around us, has great significance for those who ponder the human condition. The deep-space views of our Planet Ocean with its sweeping clouds, and moving oceans and creeping continents must rank as the greatest photograph ever taken. Viewing Spaceship Earth hanging in the vast void is an almost frightening experience. We are so alone! It is easy to understand why so many are attracted to a simpler account of origins, like the allegorical tale of creation written in heroic style (but eschewing math, maps, figures, tables, references, and evidence) in the first eleven chapters of Genesis. This treatise examines the morphology of the six rocky planets and their 27 satellites from a broad perspective.

Man has a great tendency to get lost or to hide, as the case may be, in a jungle of details and in unnecessary complications. Why do anything simply if you can do it complicated? And still, life itself presents a sufficient number of problems to keep us busy. There would seem to be no need to create additional difficulties, just for the fun of it, especially if these self-made difficulties become practically insuperable and if in the end they cause much unhappiness. The morphological mode of thought and of action was conceived to break the vicious hold which the parasitic wild growth of complications exerts on life in all of its phases. Morphological thought and action are likely to be of value in all human activities, once such thought and action have been clearly delineated and fully developed, and once they have been practised by a sufficiently large number of people. Since the morphological method is of the greatest universality, the choice of the field to which one applies it first is not particulary critical. The author intends to write two or three books on the morphology of several large scale problems, which are both of a technical and of a general social nature. The present book is concerned in particular with some implications of morphological thinking in astronomy. We shall above all emphasize the basic character of the morphological approach, and we shall demonstrate its constructive power in a number of specific cases.

Sects. 12, 13. 89 sequence and that subgiant and fainter stars in globular clusters have ultraviolet excesses. When dealing with stars whose physical properties are imperfectly under stood, such as in globular cluster stars, we cannot rely too heavily on the empiri cal calibration by the kinds of stars used to define Fig. 5, to determine their true, unreddened U-B, B-V curve. But if by a combination of arguments, principally the reddening in the region of the stars we do known about, we can assign a fairly probable unreddened U-B, B-V curve to a group of stars about which we know little, the argument may be turned around. In this case some information may be gained about the energy envelope of the stars by examining the differences between the normal two-color index curves for the unknown group of stars compared to the known. In general there seem to be two possible causes for different stars defining different normal sequences in the U-B, B-V plane. One, the relative energy distribution in the continuum in the U, B and V photometry bands are different. An example of this is the effect of the Balmer depression in supergiants. This, of course, requires deviation from black body radiation curves for one or both groups of stars. This cause seems to be the dominant effect for very blue, hot stars where the depression of the continuum by absorption lines is at a minimum."

The Little Book of Stars answers, in the clearest language, the questions anyone might have about our heavenly canopy. How are stars born? How do they die? Why do they shine? How long do they shine? Is our star, the Sun, dying? How can you tell time from the stars? Or navigate? What are the measures of stars? Can we ever travel to other stars? In this engagingly written and concise book, the second in the Little Book series, noted astronomer James B. Kaler shows us "the significance that the stars have had in human life, how we have used them to tell our stories, and how we use them to find who and where we are."

"Dark matter" was first introduced by Zwicky in 1933 to resolve a discrepancy be tween the dynamical and luminous masses of the Coma cluster. In spite of tremen dous developments in observations and various theoretical attempts, the problem of dark matter has not been resolved but has rather deepened in mystery. Though it is now certain that dark matter constitutes a dominant part of the matter in the universe, its distribution and accurate abundance are not known well. Though many people believe that it consists of non-baryonic matter, no one can reject the bary onic candidate for sure. Though it may have surely played important roles in the formation of galaxies and their large-scale distribution, there exists no theory which is consistent with all the observational facts. Resolution of this frustrating situation is one of the urgent problems in astronomy, cosmology and particle physics. One obstacle for this is the diverse nature of the problem. More researchers are therefore invited to participate in this rich field. This volume contains lectures presented at the third N ishinomiya-Yukawa Memo rial Symposium on "Dark Matter in the Universe" held on 10-11 November 1988, in Nishinomiya City. This symposium was intended to present an introduction of the dark matter problem to young newcomers, and physicists and astrophysicists who had not specialized in this field. These proceedings will provide them with a comprehensive and current survey of the problem."

Three years ago the Reports on Astronomy were for the first time published in three separate parts whereby related astronomical topics were collected in one volume and each volume was kept to a size of no more than about 250 pages. The a m was to facilitate a wider distribution of individual volumes among astronomers and other scientists interested in specific subjects of astronomy. The same system was adopted for the present volume A of the IAU Transactions which covers the activities in astronomical research from January 1976 to December 1978. The Commission Presidents were invited to restrict their reports, to present a selection of the most important developments in the field of astronomy covered by their Commission, and to avoid overlaps with other Commission reports. As a re sult of the restriction in the number of pages some Commissions presen.t a large, concentrated list of references with little discussion, whereas others review some of the most exciting recent research developments in their subject. The distribution of the Commission Reports into the three parts of volume XVII A is as follows: VOL. XVII A PART 1 commission 4. Ephemerides 5. Documentation 6. Astronomical Telegrams " 7. Celestial Hechanics " 9. Instruments and Techniques 14. Fundamental Spectroscopic Data " 15. Physical Study of Cornets, Hinor Planets and Meteorites 16. Physical Study of Planets and Satellites " Working Group on Planetary System Nomenclature 17. The Moon " 19. Rotation of the Earth " 20."

This book, which has been in the making for some eighteen years, would never have begun were it not for Dr. David Dewhirst in 1976 kindly having shown the author a packet of papers in the archives of the Cambridge Obser vatories. These letters and miscellaneous papers of Fearon Fallows sparked an interest in the history of the Royal Observatory at the Cape of Good Hope which, after the diversion of producing several books on later phases of the Observatory, has finally resulted in a detailed study of the origin and first years of the Observatory's life. Publication of this book coincides with the 175th anniversary of the founding of the Royal Observatory, e.G.H. Observatories are built for the use of astronomers. They are built through astronomers, architects, engineers and contractors acting in concert (if not always in harmony). They are constructed, with whatever techniques and skills are available, from bricks, stones and mortar; but their construction may take a toll of personal relationships, patience, and flesh and blood.

Research of the interstellar medium (ISM) has been advancing rapidly during the last 10 years, mainly due to immensely improved observational facilities and techniques in all wavelength ranges. We are now able to investigate the ISM in external galaxies and even the intergalactic and intracluster medium in great detail. Increased spatial and spectral resolution have provided us with a great deal of information on the interstellar gas in its various phases, the magnetic field and the cosmic rays, and of course, also the stellar component, which is the driving agent of the interstellar matter cycle.
Since only fairly recently, a sufficient amount of computing power has become available to tackle these problems with some prospect of obtaining a self-consistent picture of the ISM, a major goal of this workshop was to bring together observers and theoreticians sufficiently close, so that intense discussions about the necessities and desiderata of modelling the ISM could be stimulated. Observers have shown in great detail on this conference of what is seen on all scales of the ISM, near and far, and what boundary conditions would be appropriate for realistic models, and theoreticians pointed out what assumptions and simplifications their codes need, and how future observations could test their models. As a first step towards this goal, some self-consistent numerical simulations with a minimum number of relevant physical processes were also presented on this meeting. There was wide agreement, that this approach - to keep observers and theoreticians in close contact and also in sometimes quite controversial discussions - will bear fruitful results in the near future.

InMay1988,theFirstInternationalConferenceonDissociativeRecombination:Theory, ExperimentandApplicationswasheldatChateauLakeLouise,Alberta,Canada. Thismeeting gaveaconsiderableimpetustothissubject,whichisofparticularinterestforalargevarietyof fieldsincludinginterstellarclouds,planetaryatmospheres,gaslasers,plasmaprocessing,ion sourcesandthermonuclearplasmas. Sincethen,indeed,severalcollaborationswereinitiated betweenexperimentalistsworkingwithdifferenttechniques,betweentheoreticiansdealingwith molecularstructureononehandanddynamicsontheotherhandandalsobetween experimentalistsandtheoreticians. Duringthelastfouryears,therefore,alargenumberof studieswerecarriedoutandraisedanewsetofquestions. Moreparticularly,theresultsthat wereobtainedconcerningcontroversialspeciessuchasH!andHeir,castingsomedoubton theverymechanismsbywhichdissociativerecombinationproceeds. The Second International Conference on Dissociative Recombination: Theory, ExperimentandApplications heldat"I'AbbayedeSaintJacutdelaMer",Brittany,France, May3-8,1992,camethereforeattherighttimetosurveythecurrentstateofthesubject. The symposiumbroughttogetherleadinginvestigatorsinthefieldsofmolecularionrecombination research,atomicandmoleculartheoryandexperiment,plasmasphysics,astrochemistryand aeronomy. Speakerspresentedtalksreviewingtheirownworkandthesewerefollowedby livelydiscussionsessions. Freetimeperiodsallowedparticipantstodiscoveranenchanting peninsulaofNorthBrittanywhilepursuingstimulatingscientificdiscussions. Thepapersinthis volumearebasedonthesetalksandfurtherdiscussions,withtheexceptionofcontributions fromT. AmanoandB. M. McLaughlinwhowereunabletoattend. Alistofparticipantsas wellasasouvenirgroupphotoisgivenattheendofthebook. WeareindebtedtoNATOforitsfinancialsupportwhichcontributedtothegreat successofthissecondmeeting. TheUniversityofRennesIandtheBalzerscompanyarealso acknowledgedfortheiradditionalsupportManythankstothewholestaffoftheabbeyforits kindnessandeffortsinprovidinguswithapropitiousenvironmentforsuchaworkshop. We arealsogratefultoL. Caubetforhervaluableadministrativeassistanceduringthepreparation ofthemeeting. Finallyaspecialmentionmustbegiventoallthesessionchairpersonsfortheir skillinorchestratingthediscussions. Lookingforwardtoattendingthethirdmeeting. TheEditors Bertrand R. Rowe J. Bria/l A. Mitchell Andre Callosa DepartementdePhysique DepartmentofPhysics DepartementdePhysique AtomiqueetMoleculaire TheUniversityofWesternOntario AtomiqueetMoleculaire UniversitedeRennesI London,Canada,N6A3K7 UniversitedeRennesI CampusdeBeaulieu CampusdeBeaulieu 35042RennesCedex, 35042RennesCedex, France France v CONTENTS ORALCONTRIBUTIONS PolyatomicIonDissociativeRecombination . 1 D. R. Bates RecentDevelopmentsandPerspectivesintheTreatmentofDissociative RecombinationandRelatedProcesses...11 A. Giusti-Suzor, I. F Schneider, and 0. Dulieu CharacteristicsofSuperexcitedStatesofMoleculesandMQDTStudiesofNO+ DissociativeRecombination...25 H. Sun, K. Nakashima, and H. Nakamura CalculationsforAr +Xe*andArXe+ +e 35 A. P. Hickman, DL Huestis, and R. P. Saxon Electron-IonContinuum-ContinuumMixinginDissociativeRecombination 47 s. L. Guberman ATheoreticalStudyoftheHCO+andHCS+ElectronicDissociativeRecombinations. . 59 D. Talbi, and Y Ellinger DissociativeRecombinationofCH;:SomeBasicInformationfromElectronic 2 StructureCalculations. 67 WP. Kraemer TheoreticalProblemsintheDissociativeRecombinationofH~ +e...75 H. Takagi RecentMergedBeamsInvestigationsofHydrogenMolecularIonRecombination...87 J B. A. Mitchell, F B. Yousif, P. Van der Donk, and T. J Morgan vii FlowingAfterglowStudiesofElectron-IonRecombinationusingLangmuirProbesand OpticalSpectroscopy...99 NG. Adams RecentFlowingAfterglowMeasurements . 113 B. R. Rowe InfraredSpectroscopicStudiesoftheDissociativeRecombinationProcessesofH...127 3 T. Amano RecombinationofClusterIons . 135 R. Johnsen PredissociationofExcitedStatesofH . . 145 3 H. Helm AStudyofHe e,3I,;)BoundandContinuumStates...155 2 CJ Gillan, B. M McLaughlin. and P. G. Burke ElectronCollisionInducedExcitationsandDissociationofHeH+usingthe R-MatrixMethod . . 163 BK Sarpal, J Tennyson, and L. A. Morgan AssociativeIonisationofHydrogen:ExperimentswithFastMergedBeams...173 F Brouillard, andX Urbain TheoryoftheAsssociativeIonisationReactionbetweenTwoLaser-Excited . 187 SodiumAtoms 0. Du!ieu, A. Giusti-Suzor, andF Masnou-Seeuws ResonantTheoryofDissociativeAttachment...195 J. J. Fabrikant MicroscopicandMacroscopicTheoriesofTermolecularRecombinationbetween AtomicIons...205 MR. Flannery DissociativeRecombinationinPlanetaryIonospheres . . 219 JL. Fox ChemistryofSupernova1987a . 243 A. Dalgarno DissociativeRecombinationinInterstellarClouds . .

Neutrinos play a fundamental role in the latest particle physics theories, such as Grand Unified Theories, theories of supersymmetry, and superstring theory. Their mass yields an important boundary condition for grand unification models. They are the best candidates for dark matter in the universe, and their mass could determine its large scale structure and evolution. Neutrinos probe the interior of collapsing stars, and understanding them may lead to a solution of the solar neutrino problem. In ten chapters written by experts in each of these fields this book gives a comprehensive presentation of our current knowledge of the neutrino, of its role in nuclear particle and astrophysics theories, and of ongoing experimental efforts to learn more about its own nature. Graduate students and researchers in these fields will find this book a reliable advanced text and source of reference.

Nobel Symposium No 31 on The Impact of Space Science on Man kind was held at Spatind, Norway, September 7 - 12, 1975. Twenty seven leading experts from the United States, the U. S. S. R. and Western Europe attended the Symposium. Four main subjects were discussed: The Impact of Space Science, introduced by Profe. ssor Reimar Lust; The Impact of Space Communica tion, ihtroduced by Dr Joseph Charyk; The Impact of Earth Resources Exploration from Space, introduced by Dr William Nordberg; and The Impact of Space Assisted Meteorology, introduced by Dr Robert M White. This book contains edited summaries of the papers presented at the Symposium and summaries of the discussions. The Symposium was financed by the Nobel Foundation through grants from the Tercentenary Foundation of the Bank of Sweden and organized by a special committee appointed by the Norwegian Nobel Institute. Tim Greve Finn Lied Erik Tandberg vii CONTENTS The Impact of Space Science 1 R. Lust The Impact of Space Science on Mankind (Discussion) 13 T. R. Larsen (ed. ) Satellite Communications 25 J. V. Charyk The Impact of Space Communication (Discussion) 57 G. Rosenberg (ed. ) The Impact of Earth Resources Exploration from Space 67 W. Nordberg The Impact of Earth Resources Exploration from Space 79 (Discussion) E. Tandberg (ed. ) The Environmental Satellite: What It Means for Man 91 R. M. White The Impact of Space Assisted Meteorology (Discussion) 111 E. Tandberg (ed.

Although the development of ideas about the motion and trajectory of comets has been investigated piecemeal, we lack a comprehensive and detailed survey of ph- ical theories of comets. The available works either illustrate relatively short periods in the history of physical cometology or portray a landscape view without adequate details. The present study is an attempt to review - with more details - the major physical theories of comets in the past two millennia, from Aristotle to Whipple. My research, however, did not begin with antiquity. The basic question from which this project originated was a simple inquiry about the cosmic identity of comets at the dawn of the astronomical revolution: how did natural philosophers and astronomers define the nature and place of a new category of celestial objects - comets - after Brahe's estimation of cometary distances? It was from this turning point in the history of cometary theories that I expanded my studies in both the pre-modern and modern eras. A study starting merely from Brahe and ending with Newton, without covering classical and medieval thought about comets, would be incomplete and leave the fascinating achievements of post-Newtonian cometology unexplored.

Since the 1970s symposia or colloquia devoted to recent research on close binaries have been held around the world almost annually. At meetings of the General Assembly of the International Astronomical Union this topic has also been discussed in detail at presentations in various commission meetings and also as invited talks by leading astronomers in the field. In recent years, fundamental changes have taken place in the study of close binaries due to the improvements in observational techniques, extension of observations from X-ray to radio regions of the electromagnetic spectrum, and advances in theoretical studies. For more than a decade, a group of astronomers at Ege University Observatory has been concentrating on active close binaries with particular emphasis on the behaviour of the light curves of chromospherically active systems. Thus, we decided to organize an international meeting in Western Anatolia, where this part of Turkey had been the cradle for great developments in science during antiquity. KUljadasi, located only minutes away from Ephesus, one of the seven wonders of the world, was selected to be the meeting site. Close binary systems constitute a very rich source of information about the physical properties of the component stars. Some systems are eclipsing variables, where periodic recurrences of eclipses are observed as comparatively brief decreases in the total brightness of the binary system. Precise methods of photometric observations make it possible to obtain the light variations of these systems because of eclipses and other phenomena.

During the past few decades we have witnessed at least two major innovations in science which have had substantial impact on technology as well as science itself, pervasive enough to modify many facets of our daily lives. We refer, of course, to the tran sistor and the laser. It is striking that now with the advent of optical bistability we may have opened the door to another such field, which combines these two aspects (transistor and laser) and has the possibility for important device applications as well as providing a unique window into the as yet not thoroughly explored frontiers of nonequilibrium statistical physics. This has prompted us to organize an international conference on the subject of optical bistability to provide an adequate means for assessing the current state of the art of this important field and to stimulate further significant developments by means of in tense technical exchange and interaction among the leading scien tists in this subject area.

It is a 10ng-standing tradition in this country for any event re1ated to solar activity to enjoy special importance. Because we enjoy the advantage of pro10nged sunny periods, we consider the incidence of some thirty c10udy days each year as a personal af- front. I cannot say that we have the facu1ty to produce solar ec1ipses in order to justify an Institute on this subject to be held in Athens, but I can say that the occurrence of a solar ec1ipse over Greece wou1d present, for optica1 and solar astronomers, the highest possibi1ity of exce11ent conditions for observation. We had this opportunity during the May 20, 1966 annu1ar solar ec1ipse over North Africa and southern Europe. At that time we had the p1easure to co11aborate with a 1arge number of research groups of various nationa1ities, who insta11ed optica1 and radio instru- ments near or in Lagonissi, which 1ay a10ng the centra1 path, in order to fo110w the ec1ipse. A first meeting was then organized in order to discuss methods of data handling and avai1abi1ity of resu1ts. After a pre1iminary discussion it was suggested that a 1ater meeting shou1d be organized when final resu1ts were avai1ab1e.

The conference recorded in this volume was one of the events organised to celebrate the centenary of the (re)establishment of the Royal Observatory, Edinburgh, on Blackford Hill in 1884. Circumstellar Matter was selected as the topic because of important contributions toward research in the field by recent observations in the infrared and submillimetre, particularly with the two telescopes which the Observatory has both operated and built instru mentation for - the United Kingdom Infrared Telescope (UKIRT) and the James Clerk Maxwell Telescope (JCMT). The programme aimed to cover as many aspects of circumstellar matter as could fit into a one-week meeting, omitting only planetary nebulae, which had been well served by meetings in the previous two years. We thank the international scientific advisory com mittee (overleaf) for their help in selecting the Invited Reviewers around which the programme was built. The Invited Reviews and oral contributions are included in the order and sections in which they were presented, even where re-ordering might have been more logical. We did not attempt to categorise the poster contributions but have included them in alphabetical order. An evening session for viewing and discussing posters in an unhurried atmosphere was very successful. A competition for the best poster was held and the prize was awarded for that by Lindqvist, Lucas, Olofsson, Omont, Eriksson & Gustafsson."