In 1807, a year after Lewis and Clark returned from the shores of the Pacific, groups of trappers and hunters began to drift West to tap the rich stocks of beaver and to trade with the Native nations. Colorful and eccentric, bold and adventurous, mountain men such as John Colter, George Drouillard, Hugh Glass, Andrew Henry, and Kit Carson found individual freedom and financial reward in pursuit of pelts. Their knowledge of the country and its inhabitants...