From the beginning of Space Astronomy, the Extreme Ultraviolet band of the spectrum (roughly defined as the decade in energy from 90-900 A...) was deemed to be the unobservable ultraviolet'. Pioneering results from an EUV telescope on the Apollo-Soyuz Mission in 1975 forcibly demonstrated that this view was incorrect; but it required the all-sky surveys of the English Wide-Field Camera and the Extreme Ultraviolet Explorer to demonstrate the broad potential of this field. Over 700 EUV sources have now been detected. Over 150 researchers from 16 countries gathered to share results in this new field at the International Astronomical Union Colloquium No. 152. Papers were presented on a wide variety of topics including cool star coronae, white dwarf atmospheres and evolution, neutron stars, the Io torus, cataclysmic variable stars, active galactic nuclei, the interstellar medium, winds and atmospheres of early type stars, and EUV plasma diagnostics. Selected manuscripts from this meeting are provided in these Conference Proceedings.

From the beginning of Space Astronomy, the Extreme Ultraviolet band of the spectrum (roughly defined as the decade in energy from 90-900 A) was deemed to be the unobservable ultraviolet'. Pioneering results from an EUV telescope on the Apollo-Soyuz Mission in 1975 forcibly demonstrated that this view was incorrect; but it required the all-sky surveys of the English Wide-Field Camera and the Extreme Ultraviolet Explorer to demonstrate the broad potential of this field. Over 700 EUV sources have now been detected. Over 150 researchers from 16 countries gathered to share results in this new field at the International Astronomical Union Colloquium No. 152. Papers were presented on a wide variety of topics including cool star coronae, white dwarf atmospheres and evolution, neutron stars, the Io torus, cataclysmic variable stars, active galactic nuclei, the interstellar medium, winds and atmospheres of early type stars, and EUV plasma diagnostics. Selected manuscripts from this meeting are provided in these Conference Proceedings."

The galactic and extragalactic background radiation components are of major importance in astrophysical studies of a variety of problems related to galactic structure, interstellar matter, the distribution and evolution of galaxies and intergalactic matter, and cosmology. The back ground radiation is a unique source of information in cases where the source is of a truly diffuse nature, as with scattering and emission by interstellar dust and gas, or where the discrete emission sources are so faint (e. g. , very distant galaxies) that they can be observed only by their integrated emission. The galactic and extragalactic background must be discussed together because they are observationally entangled and their proper separation requires a knowledge of both components. The above points are equally valid for the entire electromag netic spectrum, from gamma rays to long radio waves. Thus, the study of the galactic and extragalactic background radiation is interdisciplinary in its character, and a multi wavelength approach would appear to be dictated by the nature of the topic. The proper separation of the galactic and extragalactic background components requires a knowledge of both. In addition, the foreground components, i. e. , zodiacal light, airglow, and atmospheric scattered light, must be treated carefully.