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. However, while editing this volume I have felt that it would be more important to assure a speedy publication than to attempt to achieve a high degree of uniformity, which would anyhow be extremely diffi- cult with more than 100 eontributing contributing authors. When published, this book should stiIl still be a tool for aetive active research, not a museum pieee. piece. I am grateful to the organizers and editors of the individual sections seetions for having produced produeed their parts with within in the allotted time, and with a high degree of professionalism. A special speeial word of thanks goes to my eollaborators collaborators at the European Southern Observatory, Mrs. E. Volk, Volk, Mr. Nr. C. Madsen, and Mr. J. _Leelereqz, _Leclercqz, for technical teehnieal assistanee. assistance.
Invited Discourses.- Astronomy in Ancient Greece.- The Origin and Early History of the Sun and the Planetary System in the Context of Stellar Evolution.- Modern Cosmology.- Original and Development of Solar Flares.- Joint Discussions.- 1. Solar Luminosity Variations (Chairaman: J.A. Eddy).- 2. Evolution in Old Stellar Populations in Galaxies (Chairaman: G. Lynga).- 3. The Extragalactic Distance Scale and the Hubble Constant (Chairaman: P.W. Hodge).- 5. Origin and Evolution of Interplanetary Objects (Chairaman: B.A. Lindblad).- 6. Active Galactic Nuclei (Chairaman: F. Pacini).- 7. Mass Loss Phenomena (Chairaman: A.G. Hearn).- Joint Commission Meetings.- 1. Giant H II Complexes Outside Our Galaxy (Chairaman: J. Heidmann).- 2. UV and X-Ray Observations of Interacting Binary Systems (Chairaman: Y. Kondo).- 3. The Violent Interstellar Medium (Chairaman: V. Radhakrishnan).- 4. Coma Models (Chairaman: B.D. Donn).- 5. Beams and Jets in Extragalactic Sources (Chairaman: R.D. Ekers).- 6. The Local Supercluster and its Environment (Chairamen: G.O. Abell and B.E. Westerlund).- 7. Atomic and Molecular Data (Chairamen: W. Bonsack, J.G. Phillips and G. Traving).- Author Index.