Geophysics is a branch of science which has successfully integrated many different areas of research into a coherent whole. It represents the synthesis of various broad fields of knowledge relating to both the past and the present, and this provides a basis for speculating about the future. Since geophysical research must be pursued over the whole of our planet, into the most distant continents, and even across Antarctica, it calls for the application of all man's resources. It reconstructs the past through a process of reappraisal, reflection, and discussion; it elucidates the present and thereby leads us not only to image, to measure, and to study distant events, but also to understand better the mysteries of nature. Indeed, knowledge is the key which geophysics uses to open doors leading toward the future. Geophysics must also be accepted as a branch of fundamental research in which concerted action is an essential feature; it remains in contact with society by combining research and development and assesses the value of the knowledge acquired in terms of the contribution it makes to the welfare of mankind.