This volume entitled “Lecture Notes and Essays in Astrophysics” is the first of a series containing the invited reviews and lectures presented during the biannual meetings of the Astrophysics Group of the Royal Spanish Physical Society (“Real Sociedad Española de Física”; RSEF). In particular, it includes the conferences and reviews presented during the Astrophysics Symposium held in Madrid (Spain) in July, 2003, during the First Centennial of the RSEF.

Our aim is to offer to the specialized public, and particularly to the graduate and postgraduate astrophysics students, a number of selected comprehensive reviews on current topics presented by expert speakers (“Lecture Notes”). These are complemented by a set of chapters on more specific topics (“Essays”).

The turn of the century has been rich with new discoveries, from the detections of Extrasolar Planets to the discovery of the farthest galaxies ever seen or the detection of acceleration in the expansion of the Universe. Spain is leaving her imprint on the telescope making revolution and is promoting the construction of a 10 meter class telescope at the “El Roque de Los Muchachos” Observatory, on the Island of La Palma, Spain. This book provides an interesting insight into selected topics of modern Astrophysics as developed by Spanish astronomers.