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

Product Description: This volume tries to summarize the status of observational knowledge of the Kuiper Belt. Its recent discovery has revitalized the astromomical study of the Solar System and is beginning to open new and unexpected windows on the physics of planetesimal accretion...read more (view table of contents, read Amazon.com's description)

There is hardly any field of human endeavour which is more fundamental than the study of our surroundings. We have always wanted to learn what was behind our horizon, beyond the next mountain, on the other side of the ocean, on the next planet, at the end of the Universe. We have come a long way since our early ancestors gazed upon the sky in amazement. Giant optical and radio telescopes now allow us to "see" the early epochs of the Universe, revealing phenomena beyond our comprehension. Spacecrafts with on-board astronomical instrumentation circle the Earth and fly to the limits of the Solar System, providing invaluable new information about nearby and distant objects. Many people have the intuitive feeling that it is "easier and better" to study the Universe from above the Earth's atmosphere. However, this is only partially true in as much as electromagnetic radiation of certain wavelengths (e.g. X-rays) does not penetrate the atmosphere and can only be studied from balloons and space crafts * The advent of space-borne astronomy has not made ground-based observations obsolete - on the contrary, it is only thanks to the combination of the two that we have now a vastly more comprehensive picture of the Universe than just a few decades ago.

Product Description: The XVlllth General Assembly of the International Astronomical Union was held in Patras, Greece, from 17-26 August 1982. It was marked by the tragic death of the President of the IAU, Professor M.K.V. Bappu, on August 19, 1982. This sad event, without precedent in the history of the Union, posed serious problems to the organization of the General Assembly, which could only be overcome by the full collaboration of all members, the organizers, and the Executive Committee...read more

Product Description: Even the casual reader cannot fail to notice the somewhat uneven presentation of the contributions contributians to this volume, in particular what concerns the st style. yle. A closer scrutiny will also reveal that whereas the English language is certainly the preferred vehicle for commu nication in astronomy, it is not the mother tongue of all contributors...read more