Physicists believe that known laws should suffice to explain the Earth's behavior, but the complexities of geology have defied simple explanation. Today three developments are helping to solve the problem. First, summary interpretations such as the centennial project of the Geological Society of America are being compiled of the upper 1% (60 km) of the Earth's radius. Second, new methods show the behavior at great depths in the Earth. Third, combining these studies suggests which physical laws apply at various depths. In the mantle the pattern of convection by viscous fluid flow is becoming clear. Upwelling plumes start rifts which fragment the lithosphere. Subduction carries plates down. In the strong lithosphere the Coulomb-Navier laws of brittle failure apply and confine fractures to three types corresponding to plate boundaries. Other laws determine where island arcs form. The idea that some large areas of the surface act independently of the surrounding areas if becoming recognized and simplifies analysis. One large area which behaves independently lies in the southwestern United States. These developments and the observation that most plate boundaries are elevated provide a means of applying laws of physics to classifying ranges, including folded mountains, island arcs, rifts, and ridges, into three classes and many subclasses, illustrated by examples. ¿ American Geophysical Union 1990