John Muir: mountaineer, conservationist, and writer; John Muir and His Legacy: The American Conservation Movement, by Stephen R. Fox. Boston: Little, Brown & Co. $17.50.

Pick up a Sierra Club calendar these days and you're likely to find the inspirational words of John Muir, the club's first president and even now the guiding spirit of environmentalism. Few owners of the calendars, however, may know that the Scottish emigrant was for part of his life (1838-1914) a "nature-struck tramp" who dropped out of college, fled to Canada to avoid the Civil War draft, wandered across-America, tinkered with inventions, and had trouble holding a job.

But the story of how John Muir -- ne'er-do- well and social misfit -- transformed himself into John Muir -- mountaineer, respected writer, and ecological visionary -- absorbing as it is, is only part of this fascinating book. Historian Stephen R. Fox has fashioned a lively and compelling intepretative study of the American conservation movement from the late 19th century to the present. "John Muir and His Legacy" is a skillful blend of personality profiles and an analysis conservation ideologies and political campaigns which integrates the rise of conservatism into broader currents of general US history.

Readers will be fascinated not only by Muir, whose admirers were as diverse as Ralph Waldo Emerson and Teddy Roosevelt, but also by a host of conservation pioneers. They will learn about gifford Pinchot, head of the US Forest Service under TR, whose phillosophy of professional outdoors management put him at loggerheads with radical amateurs in the Muir mold; William Temple Hornaday, the reformed big-game hunter who ran the Bronx Zoo; Will Dilg, whose Midwest-based Izaak Walton League became for a time the largest conservation group in the country; Rosalie Edge, the activist nemesis of the Audubon Society; and Robert Marshall, a socialist founder of the Wilderness Society.

Forget any stereotypes about high-minded ladies and gentlemen quietly recording bird species. Name-calling and jostling for position are as much a part of Fox's story as hiking the Sierras and saving the wilderness. Dilg, for instance, was kicked out of his job for spending double the Izaak Walton League budget; Hornaday of the Bronx Zoo dismissed Aububon founder George Bird Grinnell as "The Great Stuffed Prophet."

For all its liveliness, though, "John Muir and his Legacy" is a serious study of organizational expansion and decline, political wins and losses, and changes in conservation thought. Fox charts the tide shifts in recent decades, as narrowly focused conservation interests have matured into an expansive "environmentalism" anxious about humankind's ultimate fate. In an age of soaring world population and the proliferation of nuclear power and weapons, human survival itself has taken top spot on the conservation agenda.

Paradoxically, Fox points out, Muir's belief that man is not at the center of the universe no longe seems eccentric. If man would save himself, the new ecology teaches, he should lose himself, shed his arrogance about human superiority to other living things. otherwise, "progress" may lead to Doomsday.

If Fox occasionally veers from scholarly detachment, it is to side with such smaller, leaner, more militant groups as the Wilderness Society, which carry on Muir's tradition of radical amateurism. His portraits of more conservative organizations and thier leaders, such as the National Wildlife Federation, suffer by comparison. Still, the author can reverently describe Friends of the Earth leader David Brower as "Muir incarnate," yet grant that he is as headstrong as he is gifted.

The first two-thirds of "John Muir and his Legacy," for which Fox has an abundance of documentary sources from inside conservation groups, are necessarily stronger than the chapters on recent times. Even so, the book will serve very well for now as an overview of conservationism in America. Best of all, Stephen R. Fox is a lucid stylist, which is why leaders with any interest in the out-of-doors, or the reform impulse in America, can turn to this book for new understanding of our place in the scheme of things.