A union list of serials commencing publication after Dec. 31, 1949.

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.

Although the Milky Way is the most studied and best understood galactic system, there are many fundamental questions about our Galaxy that remain unanswered. This book concentrates on those questions which have the widest applicability in all of astrophysics, and for which answers are most likely to be forthcoming in the next few years. Is the Milky Way a barred spiral, and if so, what are its properties? Is the disk of the Milky Way axisymmetric and what does the answer tell us about its dynamical history? Is there a black hole at the center of the Galaxy? How far does the Galaxy extend? How much dark matter is there in the Milky Way system? And more.

Astronomy isthemostancientsciencehumanshavepracticedonEarth. Itisascienceofextremesandoflargenumbers:extremesoftime–fromthe big bang to in?nity –, of distances, of temperatures, of density and masses, ofmagnetic?eld,etc.Itisasciencewhichishighlyvisible,notonlybecause stars and planets are accessible in the sky to the multitude, but also - cause the telescopes themselves are easily distinguishable, usually on top of scenic mountains, and also because their cost usually represent a subst- tialproportionofthenation’sbudgetandofthetaxpayerscontributionsto that budget. As such, astronomy cannot pass unnoticed. It touches on the origins of matter, of the Universe where we live, on life and on our destiny. It touches on philosophy as well as on religion. Astronomy is the direct c- tactofhumankindwithitsoriginsandtheimmensityofuniversalnature.It is indeed a science of observation where experimentation is practically - possible and which is ruled by mathematics, physics, chemistry, statistical analysis and modelling, while o?ering the largest number of veri?cations of the most advanced theories of fundamental physics such as general r- st ativity and gravitation. At the beginning of the 21 century astronomy is clearly a multidisciplinary activity touching on all aspects of science. It is therefore logical that in the past and still now, astronomy has attracted the most famous scientists, be they pure observers, mathematicians, physicists, biologists, experimentalists, and even politicians.

Strasbourg Astronomical Observatory is quite an interesting place for historians: several changes of nationality between France and Germany, high-profile scientists having been based there, big projects born or installed within its walls, and so on. Most of the documents circulating on the history of the Observatory and on related matters have however been so far poorly referenced, if at all. This made necessary the compilation of a volume such as this one, offering fully-documented historical facts and references on the first decades of the Observatory history, authored by both French and German specialists. The experts contributing to this book have done their best to write in a way understandable to readers not necessarily hyperspecialized in astronomy nor in the details of European history. Several appendices conclude the book: lists of council members and of Observatory scientific personnel, as well as a compendium of the institutional publications until the year 2000.

Proceedings of the 97th Colloquium of the International Astronomical Union, held in Brussels, Belgium, June 8-13, 1987