Preface; I. Appenzeller. I. Invited Discourses. Recent Advances in X-Ray Astronomy; Y. Tanaka. Earth Rotation Variation from Hours to Centuries; J. O. Dickey. The High Energy Frontier; C. Rubbia. II. Joint Discussions. Women in Astronomy; S. Torres-Peimbert. History of Astronomy; S. Débarbat. `75 Years of the IAU'. `Work in Progress'. Current Developments in Astronomy Education; J. R. Percy. Towards the Establishment of the Astronomical Standards; T. Fukushima. Nutation; V. Dehant. Timescales: State of the Art; E. Proverbio. Sun and Heliosphere - Challenges for Solar-Terrestrial Physics Magneto- and Hydrodynamics; M. C. E. Huber. Helio- and Astroseismology; W. Däppen. Dust around Young Stars: How Related to Solar System Dust? Summary; M. S. Hanner. Accuracy of the HR Diagram and Related Parameters; M. Gerbaldi. Recent Advances in Convection Theory and Modelling: Summary; S. Sofia. Stellar and Interstellar Lithium and Primordial Nucleosynthesis; F. Spite. Extragalactic Planetary Nebulae; Y. Terzian. Activity in the Central Part of Galaxies; V. Trimble. Astrophysical Applications of Powerful New Atomic Databases; W. L. Wiese. `The New Atomic Databases'. `Stellar Atmospheres'. `Stellar Structure'. The Status of Archiving Astronomical Data: Summary; R. E. M. Griffin. III. Special Sessions. The Collision of Comet P/Shoemaker-Levy 9 with Jupiter; C. de Bergh. Gravitational Lens Monitoring: Summary; J. -P. Swings. IV. Working Group Meetings: A. H. Batten. Problems of Astronomy in Africa. International Catalog Projects. Index of Authors. Language: English