The NATO ASI held in the Geophysical Institute, University of Alaska Fairbanks, June 17-28, 1991 was, we believe, the first attempt to bring together geoscientists from all the disciplines related to the solar system where fluid flow is a fundamental phenomenon. The various aspects of flow discussed at the meeting ranged from the flow of ice in glaciers, through motion of the solar wind, to the effects of flow in the Earth's mantle as seen in surface phenomena. A major connecting theme is the role played by convection. For a previous attempt to review the various ways in which convection plays an important role in natural phenomena one must go back to an early comprehensive study by 1. Wasiutynski in "Astro physica Norvegica" vo1. 4, 1946. This work, little known now perhaps, was a pioneering study. In understanding the evolution of bodies of the solar system, from accretion to present-day processes, ranging from interplanetary plasma to fluid cores, the understanding of flow hydrodynamics is essentia1. From the large scale in planetary atmospheres to geological processes, such as those seen in magma chambers on the Earth, one is dealing with thermal or chemical convection. Count Rumford, the founder of the Royal Institution, studied thermal convection experimentally and realized its practical importance in domestic contexts."

The IAU Symposium No. 47 The Moon was held in the School of Physics of the University of Newcastle-upon-Tyne, England, from 22 to 26 March 1971. The Meet- ing was sponsored by Commission 17 and co-sponsored by URSI. The Symposium was supported financially by the IAU. The Scientific Organizing Committee included Prof. S. K. Runcorn, Chairman (University of Newcastle-upon-Tyne), Prof. H. Alfven (Royal Institute of Technology, Stockholm), Prof. G. Colombo (University of Padova), Prof. A. Dollfus (Observatoire de Paris), Prof. T. Gold (Cornell University), Dr K. Koziel (Jagellonian University, Poland), Prof. G. P. Kuiper (University of Arizona), Dr B. J. Levin (U. S. S. R. Academy of Sciences), Dr A. A. Mikhailov (U. S. S. R. Academy of Sciences), Prof. A. E. Ringwood (Australian National Univer- sity) and Prof. H. C. U rey (University of California). The Local Organizing Committee included Prof. S. K. Runcorn (Chairman), Dr G. Fielder, Prof. W. R. Hindmarsh, Prof. Z. Kopal and Prof. W. H. McCrea. This book includes the majority of papers presented at this the second IAU Sym- posium on The Moon: comparison with the previous IAU Symposium on The Moon held in Leningrad, a decade earlier, makes clear the great advances made possible in our knowledge of the Moon and solar system by space technology. Academician A. A.

This volume presents lectures given at the NATO Advanced Study Institute held 11-22 April 1988 at Newcastle upon Tyne, England. The aim of the Institute was to improve the interaction between workers in observational geomagnetism (using historical data) and archaeo- and palaeo-magnetism (using the remanent magnetization of man-made artefacts and of natural sediments and rocks) and those trying to interpret the data in terms of mechanisms inside or outside the Earth, particularly those developing dynamo theories of the field. The material discussed ranged from magnetic bacteria swimming round a circle in a few seconds, the effect of El Nino, through secular variation with time scales of tens to thousands of years and the'mechanics of individual field reversals and excursions (aborted reversals?) to possible modulation of average reversal frequency on the hundred million year time scale. Many members of the Physics Department helped with the organization, and we are most grateful to them, and in particular to Anne Codling for her very many contributions. We also gratefully acknowledge the painstaking work of Aileen Dryburgh and Lynn Whiteford in so carefully typing the manuscript.

The NATO ASI held in the Geophysical Institute, University of Alaska Fairbanks, June 17-28, 1991 was, we believe, the first attempt to bring together geoscientists from all the disciplines related to the solar system where fluid flow is a fundamental phenomenon. The various aspects of flow discussed at the meeting ranged from the flow of ice in glaciers, through motion of the solar wind, to the effects of flow in the Earth's mantle as seen in surface phenomena. A major connecting theme is the role played by convection. For a previous attempt to review the various ways in which convection plays an important role in natural phenomena one must go back to an early comprehensive study by 1. Wasiutynski in "Astro physica Norvegica" vo1. 4, 1946. This work, little known now perhaps, was a pioneering study. In understanding the evolution of bodies of the solar system, from accretion to present-day processes, ranging from interplanetary plasma to fluid cores, the understanding of flow hydrodynamics is essentia1. From the large scale in planetary atmospheres to geological processes, such as those seen in magma chambers on the Earth, one is dealing with thermal or chemical convection. Count Rumford, the founder of the Royal Institution, studied thermal convection experimentally and realized its practical importance in domestic contexts."