This book is the first comprehensive description of the development of the discipline of astronomy in the Extreme Ultraviolet (EUV) wavelength range (≈ 100–1000 Å), from its beginnings in the late 1960s through to the results of the latest satellite missions flown during the 1990s. It is particularly timely to publish this work now as the Extreme Ultraviolet Explorer, the last operational cosmic EUV observatory, was shut down in 2001 and re-entered the Earth's atmosphere in early 2002. Although new EUV telescopes are being designed, it will be several years before a new orbital observatory can come to fruition. Hence, for a while, progress beyond that reported in this book will be slow.

We intended this book to be for astrophysicists and space scientists wanting a general introduction to both the observational techniques and the scientific results from EUV astronomy. Consequently, our goal has been to collect together in a single volume material on the early history, the instrumentation and the detailed study of particular groups of astronomical objects. EUV observations of the Sun are not within the scope of this current work, since the Sun can be observed in far more detail than most sources of EUV emission, providing material for a book on its own. We have found it useful to deal with the subject in its historical context. Therefore, we do not have specific chapters on instrumentation but integrate such material into the development of the scientific results on a mission-by-mission basis.