The Mediterranean Sea, nestled between Africa, southern Europe, and the Middle East, may be envisioned as a complex picture-puzzle comprising numerous intricate pieces, many of which are already in place. A general image, in terms of science, has emerged, although at this time large gaps are noted and some areas of the picture remain fuzzy and indistinct. In recent years this fascinating, mind-teasing puzzle image has become clearer with individual pieces more easily recognized and rapidly emplaced, largely by means of multidisciplinary and multinational team efforts. In this respect, the Special Program Panel on Marine Sciences of the NATO Scientific Af fairs Division considered the merits of initiating four conferences bearing on the Mediterranean ecosystem. It was suggested that the first, emphasizing geology, should dovetail with subsequent seminars on physical oceanogra phy, marine biology, and ecology and man's influence on the natural Medi terranean regime. At a conference held in Banyuls-sur-Mer, France, in August 1979, Profes sor Raimondo Selli was urged by some panel members to initiate an Ad vanced Research Institute (ARI) that would focus primarily on the geologi cally recent evolution of the Mediterranean Sea and serve as a logical base for future NATO conferences on the Mediterranean."