At any international gathering these days the dominant theme is likely to be the obvious interdependence of all nations in a global environment that is now perceived to be sharply limited. There is, of course, nothing new in the twin concepts that the world is one and that it is not infinite. For some years prophets, statesmen, scholars, and humble citizens have been blowing on these two horns with increasing vigor. But it took the oil shock of the autumn of 1973 to transform these ideas from the realm of provocative theory to chilling reality. An interdependent, limited world was until quite recently an interesting, slightly worrisome concept, but hardly more immediately threatening than the theory of an ever expanding universe. Suddenly it seems more like the hypnotic eye of a striking cobra, inducing a mixture of terror and immobility.