The International Astronomical Union (IAU) was founded in 1919, in the wake of the First World War, together with its sister Unions in related natural sciences. It will thus turn 100 years in 2019. Written by a mixed team of insiders and outsiders, this book presents the IAU in the changing context of the historical, scientific and technological development of astronomy during the past 100 years. While much important scientific progress took place already before 1945, the book naturally focuses on the accelerating evolution during the second half of the century. In the past few decades, the previously narrow IAU focus on organising professional astronomy has broadened to include societally relevant activities such as addressing the hazard of asteroid impacts, the planetary status of Pluto in the Solar System, and the hugely successful International Year of Astronomy. Most recently, it is spearheading a combination of science literacy and public outreach. The book will be of interest to professional astronomers as well as an astronomically interested general audience. The book features live personal interviews with as many of the key actors as still possible.

IAU Transactions XXIIIB summarizes the work of the XXIIIrd General Assembly. The addresses given during the Inaugural and Closing Ceremonies are reproduced in Chapters I and III, respectively. The Proceedings of the two sessions of the General Assembly, including the Report of the Finance Committee, will be found in Chapter II. The Report of the Resolutions Committee and the Resolutions approved by the General Assembly are found in Chapter IV. The Accounts for 1994-1996 and other aspects of the administration of the Union are recorded in Chapter V, which constitutes the Report of the Executive Committee and thus provides the permanent record of the activities of the Union in the period 1994-1997. Chapter VI of this volume contains the reports of the Commission meetings in Kyoto, provided by the Commission Presidents. The Statutes, Bye-Laws and Working Rules of the Union as revised at the General Assembly are published in Chapter VII, while an updated version of the Rules for Scientific Meetings is given in Chapter VIII. Finally, Chapter IX contains lists of the countries adhering to the Union and of its approximately 8300 individual members, ordered by geographical location and commission membership as well as alphabetically (with full addresses). The IAU remains one of the few Scientific Unions in which a vigorous body of individual members contributes in a crucial way to the spirit and aims of the Union.

IAU Transactions XXIIIB summarizes the work of the XXIIIrd General Assembly. The addresses given during the Inaugural and Closing Ceremonies are reproduced in Chapters I and III, respectively. The Proceedings of the two sessions of the General Assembly, including the Report of the Finance Committee, will be found in Chapter II. The Report of the Resolutions Committee and the Resolutions approved by the General Assembly are found in Chapter IV. The Accounts for 1994-1996 and other aspects of the administration of the Union are recorded in Chapter V, which constitutes the Report of the Executive Committee and thus provides the permanent record of the activities of the Union in the period 1994-1997. Chapter VI of this volume contains the reports of the Commission meetings in Kyoto, provided by the Commission Presidents. The Statutes, Bye-Laws and Working Rules of the Union as revised at the General Assembly are published in Chapter VII, while an updated version of the Rules for Scientific Meetings is given in Chapter VIII. Finally, Chapter IX contains lists of the countries adhering to the Union and of its approximately 8300 individual members, ordered by geographical location and commission membership as well as alphabetically (with full addresses). The IAU remains one of the few Scientific Unions in which a vigorous body of individual members contributes in a crucial way to the spirit and aims of the Union.

Since 1967, the main scientific events of the General Assemblies of the International Astronomical Union have been published in the separate series, Highlights of Astronomy. The present Volume 11 presents the major scientific presentations made at the XXIIIrd General Assembly, August 18-30, 1997, in Kyoto, Japan. The two volumes (11A+B) contain the texts of the three Invited Discourses as well as the proceedings or extended summaries of the 21 Joint Discussions and two Special Sessions held during the General Assembly.

Since 1967, the main scientific events of the General Assemblies of the International Astronomical Union have been published in the separate series, Highlights of Astronomy. The present Volume 11 presents the major scientific presentations made at the XXIIIrd General Assembly, August 18-30, 1997, in Kyoto, Japan. The two volumes (11A+B) contain the texts of the three Invited Discourses as well as the proceedings or extended summaries of the 21 Joint Discussions and two Special Sessions held during the General Assembly.

Since 1967, the main scientific events of the General Assemblies of the International Astronomical Union have been published in the separate series, Highlights of Astronomy. The present Volume 11 presents the major scientific presentations made at the XXIIIrd General Assembly, August 18-30, 1997, in Kyoto, Japan. The two volumes (11A + B) contain the text of the three Invited Discourses as well as the proceedings or extended summaries of the 21 Joint Discussions and two Special Sessions held during the General Assembly.

Since 1967, the main scientific events of the General Assemblies of the International Astronomical Union have been published in the separate series, Highlights of Astronomy. The present Volume 11 presents the major scientific presentations made at the XXIIIrd General Assembly, August 18-30, 1997, in Kyoto, Japan. The two volumes (11A + B) contain the text of the three Invited Discourses as well as the proceedings or extended summaries of the 21 Joint Discussions and two Special Sessions held during the General Assembly.

Since 1967, the main scientific events of the General Assemblies of the International Astronomical Union have been published in the separate series, Highlights of Astronomy. The present Volume 11 presents the major scientific presentations made at the 23rd General Assembly, August 18-30, 1997, in Kyoto, Japan. The two volumes (volumes 11A and 11B) contain the text of the three invited discourses, as well as the proceedings or extended summaries of the 21 joint discussions and two special sessions held during the General Assembly.

Since 1967, the main scientific events of the General Assemblies of the International Astronomical Union have been published in the separate series, Highlights of Astronomy. The present Volume 11 presents the major scientific presentations made at the 23rd General Assembly, August 18-30, 1997, in Kyoto, Japan. The two volumes (volumes 11A and 11B) contain the text of the three invited discourses, as well as the proceedings or extended summaries of the 21 joint discussions and two special sessions held during the General Assembly.