Another pleasant trip with the professor with the inquiring eye, this time for a climb up the Beartooth range in the Montana Rockies, and excursions into earth sciences. The University of Virginia theoretical physicist has found a winning formula for popularization in this print version of a PBS science extravaganza. Trefil's excursion begins with a reprise of the now-familiar story of plate tectonics: the evidence that the earth's surface is composed of a dozen or so plates that float above the crest, sliding and colliding in a planetary dance that has created such phenomena as the Beartooth range. He also supplies asides on Alfred Wegener, the meteorologist often touted as the ""continental drift"" prophet. Trefil explains the differences between Wegener's theory and plate tectonics, which, while not detracting from the man's contributions, makes clear why several decades passed and new evidence from paleomagnetism and seafloor spreading was needed before the tide turned in favor of moving continents. The rocks that form the crest are the next focus for Trefil's eye, and he provides neat layman's explanations of the major types--sedimentary, igneous, metamorphic--and of how rocks are dated and the age of the earth and universe inferred. He describes their structure in atomic terms and why the various assemblages of minerals (all ending in ""ite"") are the scourge of geology students. Then, as though traversing the Greek categories of earth, air, fire and water, Trefil concentrates on water and its marvelous anomalies, not the least of which is the well-known property of expanding upon freezing. Observations of white water in mountain streams lead to more heavy-going analyses of hydraulics and hydrodynamics. All sorts of lessons are to be learned from watching the waves and eddies, the turbulence and foam, that mark the presence of submerged rocks upstream, or a smooth or pebbly bottom, The principles and laws translate to the movement of bodies in air, from raindrops to skydivers, from airplanes to meteorites, all illustrating various aspects of laminar flow or inertia, viscosity and drag, streamlining and sonic booms. Final chapters touch on the concept of ""chaotic forces""--so-called because outcomes are unpredictable even though initial conditions may be reasonably well-defined. From chaos it is a short step to the breakdown of symmetry, occasioned by Trefil's observation of the predominant right-hand twisting pattern of growth seen in trees growing at the timberline in mountains. Trefil's elaborates thereon, ending with the asymmetry that is presumed to have occurred in the first moments of the birth of the universe that led to a universe in which matter dominates over antimatter. . .yet another triumph for the peripatetic popularizer.