An asthenolith is defined as a body of magma, locally melted anywhere, at any time during geologic past and present, within any solid portion of the globe. Melting is attributed to generation of heat by atomic (radioactive) disintegration. The distribution of heat generators (radioactive minerals) is assumed to have been very irregular since some unknown initial stage. The proportion of active minerals has been in general one part in one billion or less; i.e., of the order of poverty of radioactive minerals in surface rocks. But local richness or poverty has been more or less. The life history of an asthenolith comprises local melting, growth, migration, cooling, solidification, remelting and attendant effects, in repetition. The end is intrusion into the outer crust as batholith or extrusion as lava field. The result of two thousand million years of asthenolithic activity is the crust as we find it, with more . . .