Naturalist and historian, Ferguson (The Yellowstone Wolves
) begins this sturdy, well-crafted book sensibly with the paleogeology, climatology, flora and fauna of the 300,000-square-mile Rocky Mountain range. Absorbing as these passages are, with an easy flow of captivating information, it is when the author turns his hand to describing the variety of human characters who have wandered in the Rockies through the ages that the narrative moves with the exhilaration of a kayak run in a mountain river. Folklore heroes, the trappers, guides and assorted mountain men were truly larger than life and came from the gamut of society, including wealthy and middle-class backgrounds, country and city, freed and escaped slaves. Contrary to the stereotypes, these were not uncouth rowdies who could not make it in more typical circumstances. While the author cites many famous mountain heroes, including Kit Carson and General Frémont, the lesser-known adventurers are just as fascinating. Moving through history, the reader experiences the gold fever that was near pandemic in 19th-century America, the hippie influx of the 1960s and more. There is also a thoughtful analysis of the contemporary situation in the Rockies. From extreme sports adventurers and casual hikers to developers, the mountains are under increasing environmental duress, and Ferguson is an important voice on these issues. Illus. (June)