The archdruid is David Brower, former executive director of the Sierra Club and a militant conservationist of spectacular accomplishments, and this a pointillist portrait of Brower in situ among gifted representatives of the Enemy -- a mineral engineer, a developer and a governmental dam czar. That the summit confrontations took place at all in Brower's home territory, the wilderness, was a feat in itself, and there is always the possibility that with a flap of the hand toward the natural wonders -- the Cascade Range, a pristine island off the Florida coast, the Colorado River -- the Word will be received. But geologist Charles Park continues to poke reverently for copper; developer Charles Fraser envisions a peopled paradise on his island, and the Commissioner of Reclamation proudly contemplates iris dams. For these men also have their faith and scripture, based on their version of current human need. By campsites and on trails, come moments of jovial camaraderie and blasts of anger and civil exchanges. Good men all, and yet through McPhee's appreciative evocation of place, somehow this vulnerable client of Brower's has the strongest voice. (Earlier New Yorker appearance.) Like all McPhee's work, sensitive and responsible.