The idea of Professors Bolis and Gilles to gather together for a 3 days' meeting in the splendid environment of Crans-Montana in Switzerland a limited number of people around the subject of calcium and calcium bind ing proteins seemed at first particularly attractive, and when they asked me to take charge of the scientific organization of the symposium, I accepted with enthusiasm. It rapidly became clear that the major problem would be the selection of the topics, since it was impossible to cover completely and in depth such a broad and dynamic area of research. In our view, one imperative was to associate as intimately as possible the structural and the functional aspects of the areas covered. Apart from one whole day focused on the fascinating roles played by calmodulin in cellular activities, the other sessions were devoted to calmodulin-related calcium binding proteins in muscle and non muscle tissues and to some selected biological systems such as mitochondria, secretory cells or sarcoplasmic reticulum in which calcium also plays a crucial role. The presentations were made by leading investigators in their field. Some of them do not, however, appear in the present volume, for which there are two reasons: first, some of the contributions were somewhat outside the scope of the book; second, three speakers, for valid reasons, simply found no opportunity to write a manuscript in the allotted time.