<DIV>Describing his spiritual awakening amid the mountains and valleys of central California, John Muir's <i>My First Summer in the Sierra</i> is, like <i>Walden</i>, one of the seminal texts in the literature of the American environment. It is presented here with an introduction by writer and activist Bill McKibben and related essays about Yosemite, the Hetch Hetchy Valley, and other wonders of the Sierra Nevada.</div>