This book presents the lectures and posters of some of the main leaders in the field of th magnesium research and medical applications delivered at the 8 International Symposium on Magnesium, which took place on 5-9 October, 1997 in Heraklion, Crete under the chairmanship of Professor Theophilos Theophanides. The meeting was sponsored by the National Technical University of Athens and Ministry of Industry, Energy and Technology. The aim of this meeting was to promote research and applications of magnesium and interface between medical doctors, clinicians and scientists in order to understand the mechanisms responsible for magnesium involvement in the pathogenesis of diseases, its biological significance, metabolism and many other utilizations which are associated with membranes and cells. The success of this interface is due to the contribution of its participants who came from all continents and to their high scientific level. The topics, which were presented, and the questions, which were asked, concerned mechanisms of mode of action of free magnesium cations, Mg2+, hydrated cations, 2 Mg2+. 6 HP, and magnesium linked cations Mg +.LxH 0, where L: ligand and x = 2 1...6 Hp. We would like to express our utmost gratitude to the sponsers and to extend our deep appreciation and thanks to all those who helped and encouraged the scientific and material organization of this meeting. We wish to thank all the members of the scientific committee and the organizing committee.