The universe and the solar system -- Seismology and the interior of the Earth -- Composition of the Earth -- The figure of the Earth and gravity -- Geochronology -- Isotope geology -- Thermal history of the Earth -- Geomagnetism -- Physics of the upper atmosphere -- The structure and composition of the Earth's mantle and core -- Faulting, folding, flow, and mountain building -- Theories of the Earth's behavior -- The older arguments for and against continental drift -- New evidence for continental drift from the hypotheses of sea-floor spreading and global plate tectonics -- The life cycle of ocean basins: stages of growth -- The life cycle of ocean basins: stages of decline -- The history of the earth and a possible mechanism for its behavior.