Section headings and selected papers: The International Heliospheric Study and the first COSPAR colloquium - Preface, D E Page. Introductory lecture - The heliosphere, W I Axford. Spectroscopic Data on the Local Interstellar Medium and the Related XUV Radiation Background. Characteristics of the local interstellar medium, P C Frisch. Velocity structure of the local interstellar medium, R Lallement et al. Solar UV Backscatter on Neutral Galactic Gases. Scattering of solar UV on local neutral gases, R Lallement. New channel for the photoionization of hydrogen atoms in the solar system, M A Gruntman. A lower limit on the ionization fraction of the very local interstellar medium, R J Reynolds. Entry and Dynamics of Galactic and Anomalous Cosmic Rays in the Heliosphere. Cosmic rays in the local interstellar medium, R B McKibben. The predictions of a time-dependent drift model compared with cosmic-ray intensity observations from 1976 to 1989, M S Potgieter & J A le Roux. Ion acceleration to cosmic ray energies, M A Lee. Outer heliosphere: eigen pulsations, cosmic rays and stream kinetic instability, L I Dorman et al. Distant Solar Wind Plasma, Magnetic Field and Solar Energetic Particles. Distant solar wind plasma - view from the Pioneers, A Barnes. Shock heating of the solar wind plasma, Y C Whang et al. Interaction of Solar Wind with the Interstellar Medium. Interaction of the solar wind with the external plasma, V B Baranov. The interactions of the solar wind discontinuities in the vicinity of the heliopause, S A Grib et al. Deep Space Missions. Pioneers 10 and 11 deep space missions, P Dyal. Poster Session. Author index.