Astrophysics in the extreme ultraviolet

The current status of extreme ultraviolet (EUV) astrophysics is reviewed. Seven compact emitters of EUV radiation have been identified in the <= 5% of the sky surveyed randomly so far and the existence of a diffuse EUV background firmly established. Discussion focuses on the quality of astronomical information that can be gleaned from a combined X-ray, EUV, far UV and optical study of these objects and on the impact EUV observations of the Sun and a large number of classes of compact objects will have on our understanding of the structure and evolution of evolved stars. The diffuse EUV background may be of even greater interest as it probably reveals the distribution of the hot coronal gas responsible for the interstellar OVI absorption and the source of heating and ionization of the interstellar medium. Finally, future mission possibilities are analyzed as to their potential for increased understanding of the EUV universe. (Auth.)