Autumn is the season for the Desert Southwest: specifically, for the Four Corners area, where Utah, Colorado, Arizona and New Mexico meet. Places like Recapture Wash, Goblin Valley; and Ernie's Country, Druid Arch, the Fiery Furnace; and Aladdin's Lamp Pass, Navajo Mountain, Owl Canyon and the Valley of the Gods. The cottonwoods and willows are turning gold, and the brush is amber, um- ber, ruby. The mountaintops are dusted with early snow. Days are cool, nights are crisp. It is the prime time of the year, out in America Deserta ... time to go.

We drive out into southeastern Utah from our home in southwestern Colorado on a gusty, cloudy Saturday: my wife Claire and I and our 65-pound poodle Nadine, in the old faithful '79 pickup. We have backpacks, sleeping bags, foam pads, a tent, camp stove, an armload of books, several days worth of food (including canned buffalo chili and a bottle of white wine): big loads to carry, but it is always better to carry too much than too little in the back country.

It takes us about 4 1/2 hours to drive to the jumping-off place for our hike; the last couple of miles are rough dirt track, a cattle road across a mesa-top, through scrub timber and sagebrush. When the track ends, we park the truck, get out our packs and start walking, following a sketchy trail into a shallow arroyo, the secret entrance into The Canyon. The Canyon has a proper name of course -- White, or Fry, or Fish, or Cottonwood, or Ice -- but why give it away? There are dozens of canyons out here, canyons beyond number, all of them lovely, each of them unique; pick one at random on the map and you really cannot go wrong.

There is a lot of water, a regular stream, in the arroyo bottom, and we cross and re-cross it as we descend, jumping from rock to rock, sandbar to sandbar. There is quicksand here and there, cunningly concealed beneath pebbles and coarse gravel: Step in it, and you are shin-deep in an instant; it takes a strenuous leap to break free. I recall some really bad quicksand, in Moonlight Creek Canyon down on the Navajo Reservation, a few years ago: The horse I was riding sank in up to his belly at one point, and barely managed to extricate himself. This isn't that bad -- just "quick" enough to keep the adrenaline flowing.

An hour or so later, the arroyo has become a bona fide canyon; we are still a mile and a half above the main gorge, but we are deep, deep in the earth. The blond sandstone walls rise hundreds of vertical feet on either side, decorated with water stains the color of iron, coffee. The rock is ineffably graceful, descending from the rims in breaking waves, curling surfs, molten arches, flowing ledges. The canyon floor is a series of slickrock chutes, with islands of alluvial sand bearing groves of cottonwood, thickets of willow, tamarisk, holly: an austere, Zen rock garden landscape.

The water roils down from pool to pool, swift and clear. The flash floods here, after summer thunderstorms, must be awesome: There are reefs of driftwood eight or 10 feet above our heads, timbers, branches, whole tree trunks wedged in the cliffs. In one place, the canyon bottom drops off in a 30-foot overhang; locals call these natural barriers "widow-makers," because they can be extremely hazardous to get around or over. A waterfall dangles from the lip of the overhang, drizzling down into a deep aquamarine pool. If it were 10 or 15 degrees warmer, we would take off our clothes and jump in. We reach the junction of our side canyon and the main gorge in the late afternoon. The clouds above have darkened, and it feels like it could start raining at any moment.

"Should we find a campsite here, or should we hike a little further?"

"Camp here," says Claire, sagely.

We find a flat, sandy area the size of two or three tennis courts, in the shelter of a huge overhang at the base of the canyon wall. Tether the dog to a sapling, so she can't harass the local fauna. Set up the tent. Gather firewood. Fill our water bottles at a convenient pool, build a fireplace out of cobblestones. I build a fire, and start some water heating, for wild rice; unwrap a package of bratwurst; and mix up a canteen of instant lemonade.

A single star shines through a muzzy, glowing hole in the clouds; the last light of the sun pours from over the edge of the world, igniting the canyon rims with alpenglow. We sit by the fire, and read: I am halfway through "Red Storm Rising," while Claire is immersed in a volume of S.J. Perelman. Dinner cooks; night descends. A coyote yaps, from somewhere far out in the darkness. The poodle perks her ears, but doesn't bark; she seems to realize that this is coyote turf, wilderness, someone else's place.

It is drizzling when we awaken the next morning: The chilly rain falls in thin sheets out beyond the rock overhang that shelters our camp, and falls again from the cliffs in luminous veils, lit by the pale gray predawn light.

It looks like we are in for a cold, wet day; but weather in the canyon country is unpredictable, eccentric. One minute you are hiking down a bone-dry canyon beneath a clear, scalding sky; the next minute you are crouched in a downpour up in the rocks, watching a 10-foot-high flash flood roar by. You can die of heatstroke and thirst one April day, and a day later you can be fighting through a blizzard, 40-mile-an-hour winds, blinding snows. Today is another of those tricky desert days: By sunrise, the rain has stopped, the clouds have dissolved, and the air is warming rapidly. Indian Summer, a day after impending winter: wonderful.

We breakfast on coffee, grapefruit and granola, break camp, and head down-canyon; the poodle bounds ecstatically through the sunlit water, through the wet brush, sending up big showers of spray. A pair of ravens soars overhead, braying raucous songs that echo off the cliffs. There are deer and coyote tracks in the mud and sand.

About three miles down the canyon, we come to the ruins of an Anasazi Indian village at the western edge of the canyon floor: a brush-covered, dusty mound that was the communal trash heap, with the remains of several stores and adobe buildings against the cliff, and more buildings on inaccessible ledges above. Anasazi means "Ancient Ones" in Navajo -- the Anasazis were the ancestors of today's Hopi, Zuni and Rio Grande Pueblo Indians, and they left hundreds of ruins across the Desert Southwest.

This particular village site is quite impressive: Poking around the trash midden, we find shards of painted pottery, mummified corn cobs, exquisitely chipped stone tools, hanks of knotted fiber. Many of the buildings have survived, more or less intact, in the seven or eight hundred years since they were abandoned. Here is a tiny, hobbit-sized storeroom, with the stone slab door still set in the crawl-hole doorway; over there is a circular subterranean temple, called a kiva, with the roof missing. Next to the kiva is a block of three perfect rooms, connected by low doorways; the roof beams are black with soot from old cooking fires, and we find the fingerprints of the builders in the adobe around the windows.

There is another entire neighborhood, a Stone Age condominium complex, on the ledge 30 feet above our heads: massive walls, wooden ladder-poles, exposed beams. Exploring along the cliff face, Claire finds a whole gallery of petroglyphs and pictographs, arcane signs and symbols scratched (glyphs) and painted (graphs) on the rock: hand prints, lightning bolts, desert bighorn sheep, suns, eerie big-shouldered gods with blank spectral eyes and Minotaur's horns. Powerful stuff, indeed. The Anasazis still own these canyons, in a sense. Their spirits brood over the country, watching over the ruins, the rocks, the water and sand.

We hike on down the canyon, traveling slow and easy, pausing to drink from pools, to take a dip in a deep grotto, to look into the side canyons that wind mysteriously off into the shadows and sunlight. About midafternoon, nine or 10 miles from our starting point, we find another perfect campsite, a sandy flat area sheltered by another huge overhang. The spot is high up on the western wall of the canyon, 200 feet above the canyon floor; the views up and down the canyon are astonishing.

We haul driftwood and water up from below, set up the tent, then lie back on foam pads in the sun and read for a while. A redtail hawk, a big one, cruises over the canyon rim, circles down for a closer look at us, and then wheels away and rises on the hot air like someone is reeling him in on an invisible wire.

Evening comes; the sandstone walls turn cadmium yellow, then umber, then brooding purple. We cook up buffalo chili and wild rice on the campfire, and open up the white wine, as the first stars appear ...

In November 1934, a 21-year-old poet and artist named Everett Ruess vanished without a trace in the desert of southern Utah. He had been wandering the Southwest for the better part of four years, writing poems and entries in his journal, making woodblock prints of the canyon country. His writings and pictures are preserved in a wonderful little book called "Everett Ruess: A Vagabond for Beauty," published by Peregrine Smith Books, over in Layton, Utah.

I have been re-reading Ruess on this trip (in between Tom Clancy's visions of the Third World War): passionate stuff, about long hikes, lonesome places, unbearably beautiful times. It strikes a strong chord, out here in the country that inspired it. Many people think that Ruess grew so attached to the wild canyons that he simply walked off into the wilderness and eventually perished there, of hunger or thirst. It isn't hard to understand really: Something in this severe, radiant land draws one, further and further, deeper and deeper. There is a sense of hidden mystery here: a sense that if you followed the lost gorge one more turn, or scrambled up to the sealed Anasazi storehouse on that high ledge, you would find some ultimate truth there ... the Answer to the Big Question, whatever that is. The canyon country is like that.

We break camp at midmorning the third day, and head down-canyon again, looking for an obscure route back up to the canyon rim that a friend of mine discovered a couple of years ago and marked in pencil on my map. We could go back out the way we came, but this way is quicker (if we can find it); besides, it is always fun to search out new places.

A mile or two below our last night's campsite, we find what seems like the way, looking at the marks on the map: an inconspicuous little side canyon, little more than a niche in the cliff. It doesn't look like it could possibly conceal a route up to the mesa-top, but appearances are often deceiving, out here -- you must have faith, to find the way.

We hike up this side canyon, scrambling and laboring up over boulders and ledges. The poodle is an accomplished bushwhacker and rock climber, and has no problem at all keeping up. The cliffs close in, and it looks like we have reached a dead end, when Claire finds a small heap of stones, a cairn, about 20 feet up on the sloping bedrock. Feeling a bit like characters in a backward version of "Journey to the Center of the Earth," we scurry up to it, and from there we see another, higher cairn, and another beyond that. The cliff here is not really a cliff, we notice suddenly; it is a series of sloping slickrock ramps, broken here and there by ledges -- not precisely a Sunday stroll, but far from impossible, either.

The "trail" leads on, upward: more steepish rock, then a ledge with twisted bonsai-like conifers wedged in cracks in the rock, then more steep slope, then another ledge. As we approach the rim, a last overhanging section of wall comes into view. No way around that ... But the cairns lead us to a place where the overhang has collapsed, leaving a pile of massive blocks. This is obviously the way we are supposed to go, but I don't see how the poodle can get up it: It is real hand-over-hand stuff.

I clamber part-way up the rocks, to scope out the route; I have some vague notion of climbing up, leaving my pack on the rim, and then climbing back down and hauling the poodle up, somehow. Suddenly, the dog decides to solve the problem herself: She breaks away from Claire and barrels past me, all the way up to the top, in about 1.3 seconds. She does a triumphant dance up there on the rim, barking and leaping, wagging furiously.

It takes us two more hours of steady trudging to get to the truck, across sand and rolling slickrock, through head-high scrub forests of pinåon, juniper, cedar. Far in the distance, to the southwest, the emerald dome of Navajo Mountain rears up from the rusty mesas; somewhere on its forested flanks is War God Spring, where Navajos still make offerings to the spirits of earth and tribe. To the north, the Abajo Mountains rise, their summits cloaked in storm cloud; there are black bears up there. Far, far away, to the south-southeast, the luminous turrets and plinths of Monument Valley glow beneath a lowering roof of mist. Between here and there are a hundred lost worlds, ghost pueblos, springs, grottoes.

Behind us, the canyon has completely vanished, into the convoluted mesa-top, as if it were never there. It already seems part of another world, a myth, or a dream. Rob Schultheis is covering the war in Afghanistan for Time magazine.