The contributions to this work are based on late-1990s knowledge of solar corona physics and on the prospects for future total eclipse observations, focusing on the eclipse of August 11, 1999 - the last this century - which forecasters believe will occur at precisely the maximum of solar activity. The results of past eclipse observations are reviewed, including coronal hot and cold structures, coronal heating, public education and instrumental problems. The relation of the corona to the Sun is discussed, that is, the energy and mass transfer between the chromosphere and the corona, including the formation of prominences by coronal condensation in coronal cavities and the supply of mass to the corona by spicules. The coronal heating mechanism is also discussed, that is, does heating occur in current sheets or in sheaths surrounding flux tubes? Prospects for international collaborative observations, both ground-based and from space, are presented.

The aim of this Advanced Study Institute was to give an account on the most recent results obtained in solar research. Bucharest was chosen to host it, because the capital city of Romania was located right in the middle of the totality path of the last eclipse of the millennium, on 11th August 1999; furthermore the phenomenon was close to reach there its longest duration: 2m 23s. Such a total eclipse is not only a very spectacular event which draws the crowds: to astronomers, solar eclipses still offer the best conditions for observing the lower part of the corona. The Sun plays a crucial role in our very existence. It was responsible for the formation of the Earth, and rendered this planet fit to host living beings, providing the right amount of heat, and this for a long enough span of time. Quite understandably, it has always been a prime target of human curiosity, and more recently one of scientific investigation. During the last century, it was realized that the Sun is a star like billions of others; we learned since that it draws its energy from the nuclear fusion of hydrogen, and we are now able to estimate its age and life expectancy.

The NATO ARW on the problems of ground-based observations of Solar Eclipses was held in Sinaia (Romania) between 1 and 5 June 1996. The Workshop was divided into seven sessions, in which 17 papers were given, by key speakers, along with 30 oral presentations. Additionally, 30 posters were presented. This issue contains only the invited and oral papers. The posters are to be published in a special issue of the Romanian Astronomical Journal. The contributions were based on our present knowledge of solar corona physics and on the perspectives for future total eclipse observations, focussing especially on that of August 11, 1999, which will be the last eclipse of the century. The workshop sessions reviewed the results of past eclipse observations, coronal hot and cold structures, coronal heating, public education, and instrumental problems. At the end of the meeting a fruitful general discussion drew out problems to be studied and techniques to be used for forthcoming observations. Posters completed the workshop contributions.

The aim of this Advanced Study Institute was to give an account on the most recent results obtained in solar research. Bucharest was chosen to host it, because the capital city of Romania was located right in the middle of the totality path of the last eclipse of the millennium, on 11th August 1999; furthermore the phenomenon was close to reach there its longest duration: 2m 23s. Such a total eclipse is not only a very spectacular event which draws the crowds: to astronomers, solar eclipses still offer the best conditions for observing the lower part of the corona. The Sun plays a crucial role in our very existence. It was responsible for the formation of the Earth, and rendered this planet fit to host living beings, providing the right amount of heat, and this for a long enough span of time. Quite understandably, it has always been a prime target of human curiosity, and more recently one of scientific investigation. During the last century, it was realized that the Sun is a star like billions of others; we learned since that it draws its energy from the nuclear fusion of hydrogen, and we are now able to estimate its age and life expectancy.