Invited Discourses.- A. Exploring the Moon.- B. Couches extérieures et structure interne des étoiles.- C. Radio Galaxies and Quasars, I.- D. Radio Galaxies and Quasars, II.- Joint Discussions.- A. New Techniques in Space Astronomy.- Recent Techniques in Solar Optical Astronomy from Space.- Ultraviolet Astronomy.- New Techniques in X-Ray Astronomy.- Solar and Interplanetary Magnetic Fields and Plasmas.- Infrared Astronomy.- Some Problems and Instrumental Features of Sub-millimeter Astronomy.- New Techniques in Space Radio-astronomy.- B. X-Ray Astronomy.- Surveys of X-Ray Sources.- Recent Results on Extragalactic Cosmic X-Ray Sources from Rocket and Balloon Flights.- A Cosmic X-Ray Survey in the Southern Hemisphere.- Results from Detailed Studies of X-Ray Sources.- The X-Ray Spectra of Cygnus XR-1 and the Crab Nebula.- Optical and Radio Information.- Theoretical Review.- X-Rays Radiation of a Neutron Star as a Result of Gas Accretion.- The Cosmic X-Ray Background.- C. The Lithium Problem.- The Occurrence of Lithium in Stars.- Evidence for Lithium Destruction and Synthesis in Main-Sequence and Subgiant Stars of about Solar Mass.- Observations of Beryllium in Stars.- Lithium Observations in the Sun.- On the Lithium Abundance in Sunspots and the Undisturbed Solar Atmosphere.- The Formation of Li, Be, B Isotopes by the Spallation of CNO.- What can we learn from Li and Be Stellar Observations?.- The Mixing of Lithium.- D. Modem Problems of Fundamental A strömetry.- The AGK3, SRS and Related Projects.- Recent Work on Fundamental Astrometry in the U.S.S.R.- Meridian Observations at Santiago, Chile.- Preliminary Results of the Determination of Absolute Proper Motions of Stars referred to Galaxies.- Desiderata for FK5.- Precession and Galactic Rotation on the Basis of Various Proper Motion Systems.- The Relationships between Various Techniques for obtaining Proper Motions.- The Place of Accurate Proper Motions in Galactic Research.- Études sur l’emploi de Recouvrements de Plaques pour l’établissement de Catalogues Photographiques.- The Overlap Approach toward the Derivation of Photographic Stellar Coordinates.- Report on Overlap Methods in Photographic Astrometry.- Relative Star Positions from Overlapping Photographic Plates.- E. Extragalactic Radio Sources.- Optical Studies of Extragalactic Radio Sources.- Burbidge Optical Spectra of Extragalactic Radio Sources.- Radio Observations of Angular Structure.- Radio-Source Spectra and their Time Variations.- Infrared Observations of QSS.- Millimetre-Wave Observations.- The Nature of the Red-Shifts in Quasi-Stellar Objects.- Theories proposed to explain Quasi-Stellar Objects and Radio Galaxies.- A Cosmological Interpretation of the Absorption-Line Spectra of QSO.- The Evolution of Quasi-Stellar Sources and Radio Galaxies.- The Magnetodynamic Model of Quasars.- A Rotating Disk Model for a Quasar.- Shorter Contributions.- F. Close Binaries and Stellar Evolution.- Opening Remarks.- On the Origin of the Algol Systems.- The Evolution of Close Binaries and the Formation of the Wolf-Rayet Stars.- White Dwarfs in Close Binary Systems.- Arguments indicating that Ap and Am Stars are Evolved Spectroscopic Binaries.- Investigation of Possible Abundance Anomalies in Close Binaries of Spectral Types A0-A2 & F5–F6.- The Evolution of Close Binaries and the Am Stars.- Origin of Binaries from a Consideration of Angular Momentum.- The Origin and Early Evolution of Close Binary Stars.- The Structure of W Ursae Majoris Systems.- Comments.- A Model for the Nova Outburst.- Concluding Remarks.- Special Meetings.- A. Lunar Probes.- A Description of the Lunar Orbiter Spacecraft.- Photographic Results of the Lunar Orbiter Program.- B. Coordination of Solar Observations made at Ground-Based Observatories and with Space Vehicles.- The Need of Ground-Correlated High-Resolution Space Observations in the Visible.- Space Observations Needed for Improving Our Knowledge of Solar Flares.- Space Observations of Flare Sprays and Related Surge Phenomena.- The Needs and Requirements from the Standpoint of the Ultraviolet Solar Observations.- Hard Solar X-ray Bursts.- Solar Gamma Rays and their Correlation with Space and Ground-Based Observations.- The Coordination of Ground-Based and Space Observations: Summary.
