This book contains the noted discussions of the second conference on the co-ordination of galactic research, held in Sweden in June 1957.

Since the invention of the telescope 400 years ago, astronomers have rapidly discovered countless celestial objects. But how does one make sense of it all? Astronomer and former NASA Chief Historian Steven J. Dick brings order to this menagerie by defining 82 classes of astronomical objects, which he places in a beginner-friendly system known as "Astronomy’s Three Kingdoms.” Rather than concentrating on technicalities, this system focuses on the history of each object, the nature of its discovery, and our current knowledge about it. The ensuing book can therefore be read on at least two levels. On one level, it is an illustrated guide to various types of astronomical wonders. On another level, it is considerably more: the first comprehensive classification system to cover all celestial objects in a consistent manner. Accompanying each spread are spectacular historical and modern images. The result is a pedagogical tour-de-force, whereby readers can easily master astronomy’s three realms of planets, stars, and galaxies.

This e-book contains the 2013 Revision of RDA: Resource Description and Access, and includes the July 2013 Update. This e-book offers links within the RDA text and the capability of running rudimentary searches of RDA, but please note that this e-book does not have the full range of content or functionality provided by the subscription product RDA Toolkit. Included: - A full accumulation of RDA-- the revision contains a full set of all current RDA instructions. It replaces the previous version of RDA Print as opposed to being an update packet to that version. RDA has gone through many changes since it was first published in 2010. Cataloging practice described by RDA has not changed dramatically due to the changes above, but nearly every page in RDA Print was impacted by the changes, with the result that an RDA Print update packet would require nearly as many pages as the full revision. - The most current RDA-- the revision contains all changes to RDA up to and including the 2013 RDA Update approved by the JSC. Annually the JSC considers proposals to update, enhance and maintain RDA as a current cataloging standard. These updates can and often do change the cataloging process as described by RDA. The JSC also periodically issues changes to RDA to fix errors and to clarify meaning. These changes do not typically change cataloging practice as described by RDA. - Reworded RDA-- the revision includes the reworded version of RDA instructions. To improve readability and comprehension of complex instructions, RDA has been edited and reworded since its original release. The rewording was carried out by the JSC, RDA Copy Editor, and reviewed by the U.S. RDA Test Coordinating Committee.

This book contains the noted discussions of a conference on the co-ordination of galactic research, which was held in the Netherlands, in June 1953 by the International Astronomical Union. Topics include: 'Overall structure: nuclear region and halo', 'Local structure: distribution of different types of stars in the plane' and 'Proper motions and radial velocities'.

The present volume contains papers presented during the Advanced Study Institute on the 'Structure and Evolution of the Galaxy' held under the auspices of the Science Committee, North Atlantic Treaty Organization (NATO) in Lagonissi near Athens, Greece between 8-19 September 1969. Seventeen astronomers from eight countries acted as lecturers in the Institute, which was attended by sixty-three students from twelve countries. All the lectures given in the Institute were included in the volume with the exception of two lectures given by Professor P. van de Kamp on 'Stellar Parallaxes' and 'Objects of Very Low Mass', the manuscripts of which were not submitted in time in order to be considered for publication. It is obviously impossible in a two-weeks course to cover the vast field of the Struc ture and Evolution of the Galaxy in all its aspects. Effort has been made, however, to give the students a general outline of the field. In addition to the lectures ample time was spent in discussions and personal contacts. In order to simplify the publica tion it was felt reasonable, however, not to include the discussions in the present volume.