Developments in Geotectonics, 4: The Upper Mantle focuses on the upper mantle and its influence on the development of the earth's crust, including history of the moon and other planets and volcanology. The selection first offers information on the origin of the earth, including ideas on the formation process of the terrestrial planets, condensation of dust particles, nature of the earth's core, thermal history of the earth, and fractionation of iron in the terrestrial planets. The text then ponders on the beginning of continental evolution, as well as the oldest rocks of the earth's crust, thermal history of the moon, and early history of the other planets. The text elaborates on magmatic activity as the major process in the chemical evolution of the earth's crust and mantle; trends in the evolution of continents; progress and problems in volcanology; and pressure and temperature conditions and tectonic significance of regional and ocean-floor metamorphism. The manuscript also takes a look at the state of mantle minerals, melting temperatures in the earth's mantle, and geomagnetic induction studies and the electrical state of the upper mantle. The publication is a dependable reference for readers interested in the study of the upper mantle.