Derrey sees the earth as a dynamic organism whose anatomy is partly known and whose physiology is just beginning to be probed. This theme of change, of earth seeking equilibrium but thwarted by inner upheavals, external forces (the sun), and surface effects (the action of living matter), lies always close to the surface of this lengthy treatise translated from the French by Gregor Roy. Pretty soon the reader, too, is caught up in a whirl and dazed by theory. For geology is still very much a science of hypotheses. Derrey underscores this in the early chapters by recounting the mother earth myths of early cultures down to the fanciful propositions maintained by the ""Flat-earthers"" and kindred souls still current today. Following this he discourses at length on the scientific alternative explanations for the formation of mountains and volcanoes, of continents and continental drift, for surface rock and the structure of the inner depths of the planet. He moves on to the atmosphere and the interaction between man and nature that takes place in the ""biosphere,"" at the earth's surface. In spite of allusions to the good offices of geodetic satellites and other extra-terrestial means of getting information about the earth, one feels that it is a long way before man will solve the riddles of the planet. Or perhaps geology.