Includes bibliographical references and indexes.

"The age of the earth as an abode fitted for life" (Lord Kelvin, 1899) -- Rotation, tides and the moon -- The variable sun and other astronomical effects -- The magnetic field -- Internal heat and the evolution of the earth -- The oceans -- Planetary atmospheres and the appearance of free oxygen -- Thermal balance, the greenhouse effect, and sea level -- Environmental crises and mass extinctions of species -- Stability of the environment -- Inorganic mineral deposits as products of an evolving environment -- Fossil fuels, buried carbon and photosynthetic oxygen -- Effects of fossil fuel use -- A comparison of human energy use with natural dissipations -- The cradle is rocking -- A summary of salient conclusions.