Another congenial romp-around-the-earth with geologist Parker, whose Inscrutable Earth introduced earth science to lay readers in fine style. Parker is a dedicated field geologist who romanticizes the pleasures and pains of on-site explorations and mappings. To him, earth science should have its own Greek mistress of inspiration and charm--a tenth muse. Even when he is not describing particular personal adventures, these essays evoke a strong sense of place--be it the strange sanctity of a salt mine or the anticipatory rumblings and spoutings preceding the upwelling of a geyser. An ambitious essay, ""The Buffer Did It,"" leads off, popularizing a theory he has propounded as an alternative to the various schemes of how the earth evolved. The buffer theory holds that entities such as volcanoes, glaciers, rock or ice dams, or lakes are examples of systems, which like the buffer storage in a computer, store energy temporarily--until such time that the system becomes unstable. That may occur when the buffer is filled to capacity. Echoes of the buffer theory occur in later essays in which Parker describes some of the more dramatic events in earth history--like the periodic surges of glaciers capable of moving 45 feet in a day, or the spectacular bursts of Lake Missoula (Montana), which dumped as much as 500 cubic miles of water in the Northwest some 14,000 years ago. Elsewhere Parker describes the advent of new technologies such as the diamond anvil presses used to simulate the intense pressures existing at the center of the earth or the new digitized photo enhancement techniques that produce the dramatic photos of earth from space. One essay is a bit of self-indulgence on the study of fossil feces (coprolites). Others colorfully describe the ""karst"" terrains which give rise to caves and the various theories offered to explain the existence of salt domes. Contentious as geologists can be, Parker ends with current controversies on what caused the demise of species 10,000 years ago: was it climate or man-the-hunter? (Maybe both, is the Solomonic conclusion.) Lots of fresh material here for those who like their geology without blisters.