If Western byways are still untrammeled, they are hardly unsung--so it takes a certain temerity to offer up, plain, yet another visit to a medicine man or quest for a lost canyon. But in Schultheis' loose journeyings of some 20 years, the ""vastness and emptiness,"" the unknowable-ness that first attracted him (as a Kerouac-toting preppie) yield up their disparate pleasures. He has a gift for the striking analogy: ""A century ago the Sand Hills were the Serengeti of America."" Like many naturalborn travel writers, he's a splendid cataloguer: ""Among the oddments found in coyote stomachs are horned toads, armadillo armor, bumblebees, rattlesnakes, centipedes, ropes, string, tire rubber, harness buckles, birds' eggs, honey and dirt."" (""To a coyote, the whole world is a banquet."") He has a tonic, self-mocking sanity (""Danger on a quest is all right; discomfort, inconvenience are not""); a fund of exotic knowledge (""there is a Japanese sport called swanabori, in which you follow streams to their origins. . .""); a quick, light touch with an anecdote or quote (from a returning Navajo rock musician: ""We were doing great until Marvin got scared by witches and got sick""). His subjects are all the foregoing and, more fixedly: the proliferating Navajo--""a neolithic nation-state in the middle of modern America""; the Great Basin's ""dying dead seas""; the ""human wilderness"" of the Sierra Madres' Tarahumara Indians (the finest sustained sequence); the vanished Colorado River delta (a reconnoiteur almost as hellish as Philip Fradkin's in A River No More); the drought that might, any day, kill every lawn ""from Santa Monica to Omaha"" (a scenario also in line with Fradkin's projections). Schultheis is on the side of the Indians and against the despoilers and out-of-sympathy with ""Anglos"" generally. But he doesn't gush or scold. It's the backpacker mystique clear and pure (and compact)--for readers of a less intense disposition than the Abbey following (above).