The outback is the soul of Australia. This vast, raw landscape -- which has been scorched almost clean of detail by the sun, where the cattle stations are measured in square miles instead of acres, where white explorers first set foot barely a hundred years ago and where the land, sky and even the silence exert an almost mystical force -- breeds a remarkable people. Yet few Australians and even fewer visitors ever see this part of the country.

Australians call it the outback, the back country, because for the last 200 years they have turned their backs on the searing deserts of their heartland and faced the sea. And unless you have a four-wheel-drive vehicle and a month to spare, the outback is about as accessible as the dark side of the moon.

But there is another way. Across the outback, the mail comes by air, right to the front door. Small planes flown by independent contractors operate a once-a-week service to the airstrips that are an essential part of the outback cattle stations. Some of these mail planes carry passengers, and for anyone who has ever yearned to see the real Australia, the trip with the flying mailman is the perfect opportunity.

The longest of these mail runs is known as the Channel Run. It begins just after dawn every Saturday morning when Augusta Airways Flight BH001 claws into the sky above the town of Port Augusta, about 200 miles north of the South Australian capital, Adelaide. Over the weekend the plane will travel some 2,000 miles in a giant loop, delivering mail and supplies to 24 sheep and cattle stations scattered across one of the most lonely, dry and desolate stretches of outback Australia -- the longest mail run on earth.

When I took this flight in late March there were only three of us on board the twin-engine Rockwell Aero Commander -- the pilot, Ray Mundy, and another passenger, Grace, a lively middle-aged woman on her way home to Boulia, in western Queensland. Less than 10 minutes out of Port Augusta all signs of human habitation ceased. To the east the jagged peaks of the Flinders Ranges glowed red in the early sunlight. Below the plane stretched a magenta desert etched with creeks that wavered and merged like the roots of a giant tree. It was also spectacularly wet. The banks of the creeks were outlined in green and pools of water flashed as they caught the sun. Record-breaking late summer rains had turned the desert into a great inland sea, bringing a flush of unfamiliar color to the sunburnt country.

The first stop was Leigh Creek, 150 miles north of Port Augusta, where we loaded up with more bags of mail, apples, spare parts for motorcycles, ice cream, a typewriter for the policeman at Birdsville and fresh bread. "Bread, newspapers and sausages -- they're like gold out here," said Ray. Sausages? "Well, this is cattle country and they eat prime beef all the time, but sausages are real gourmet stuff."

We took off and flew across the open-pit coal mines that are the lifeblood of the town and headed for our first property, Moolawatana, at the extreme northeastern end of the Flinders Ranges. In the pilot's notes, the instructions for Moolawatana say, "Beware of sheep and other animals on the strip." There were no animals this time, but as we hit the dirt airstrip, the wheels caught in the rain-softened earth and the plane slued. Ray had to keep the revs up as we taxied back along the strip, the soft clay clutching at the wheels.

Mike Sheehan, the owner of the property, had come out to meet us in his four-wheel-drive. He ambled over to the plane -- a big man with powerful arms and a fierce grin, dressed in khaki shorts and shirt, riding boots and an indescribably battered hat. He has one of the smaller properties out here -- a little under a thousand square miles, 8,800 sheep and 5,000 cattle. "I think," he added.

Ray unloaded his mail -- a bulky sack that Sheehan hefted over his shoulder -- and they settled down for a yarn. Besides its cargo of letters and supplies, the mail plane also brings a welcome note of fresh human contact to people whose closest neighbor might be 80 miles away. They talked about the weather, about the roads that were blocked from the rain -- most of them -- and about hauling sheep out of the mud. And about dingoes, the native wild dog. It had been a good year for the dingoes. The rabbits bred up and many more dingo pups survived than usual. Local lore: If you put out dingo traps you have to poison them because a dingo will gnaw its leg off to get free and if the trap isn't poisoned, you have a three-legged dingo that can only catch sheep. As we left Sheehan's property we flew low over the Dog Fence, the 3,500-mile steel mesh that divides the sheep pastures from dingo country -- Australia's answer to the Great Wall.

From Moolawatana we picked up the Strzlecki Track, the route alongside the creek of the same name that was pioneered by Henry Radford, also known as Captain Starlight, to drive stolen cattle down from Queensland. All morning we zigzagged across the track from one property to the next in a series of aerial hops that lasted anything from 10 minutes to half an hour.

The country here was no longer green, but parched and chafed, and wrinkled with red sand hills. The Aborigines who first inhabited this land believed it was created by giant mythical beings who shaped the country simply by singing it into existence. From a thousand feet up, the creek beds and the silvery clumps of saltbush became the squiggles and dots of Aboriginal symbolic painting -- an ancient brown calligraphy, tinged with secret meaning.

At each stop the procedure was the same. Ray would call up the homestead over the radio just before we were due to land, fly low over the strip to check that it was clear, swing the plane around in a steep banking turn and land.

The strips varied from clay pans to the bone-rattlers strewn with fist-sized pebbles known as gibbers. The gibber strips are murder on the undercarriage, but the soft clay pans are treacherous in the rain. There's a trick to getting the plane off a sticky clay pan: Get the nose wheel up quickly so it doesn't dig in and balance on the main landing gear until the plane reaches flight speed. How do you know if a strip is too wet to land? "Usually the property owners will tell you," said Ray, "but sometimes you'll have a spare part on board they've been waiting on, and then they might stretch the truth a bit."

At Moomba we crossed the gas pipeline that runs across the desert floor in a dead straight line toward Sydney.

At Innamincka we delivered the ice cream -- a miracle for a toothy little boy in the back of his dad's truck. Innamincka lies on the banks of Cooper Creek, near the spot where explorers Robert Burke and William Wills perished on the return leg of their south-to-north journey across the continent in 1860. The Dig Tree, where food was buried for the survivors of their expedition, is just across the border in Queensland.

This is Kidman country, and many of the mud-splattered four-wheel-drives that came out to meet the plane bore the insignia of the company that was founded by Sir Sidney Kidman, the famous outback cattle baron.

By midday the temperature had climbed to about 95 degrees and another 15 degrees higher in the cockpit. The smooth, steady flight of the morning had become a heaving, pitching, roller-coaster ride as the plane bucked the thermals. I'd come at the wrong time of year, it seemed. The best months are between April and October, when the air is cooler and the flying is a lot more comfortable. The tin roofs of Birdsville were a welcome sight.

Set on the edge of the Simpson Desert, Birdsville -- population 30 -- is the most isolated settlement in Queensland. The town draws its water from an artesian well almost 4,000 feet underground. After it spurts to the surface at about 150 degrees Fahrenheit, the water is cooled in open tanks and the dry wind carries the faint sulfureous smell of bore water over the town.

If you've come here along the Birdsville Track -- 300-plus miles of choking red dust -- it's been a long time between cool drinks. So the Birdsville pub is something of a shrine for travelers, but now the track was flooded over and the pub was almost empty. "Yeah, the whole world's cut off from Birdsville, the poor blighters," said the publican from behind the bar. The only other customer was Simon, a young stockman propped up on a bar stool sipping a stubbie, a squat beer bottle, with the regulation hat crammed low over his brow.

When we left the pub, a horse had taken up position in the shade of the plane's wing.

We picked up a passenger here -- a 19-year-old woman, very pregnant, going home to Bedourie to have her baby. The half-hour flight in the cramped, humid cabin wasn't a happy experience for her but she took it well. The airstrips in Queensland are a noticeable improvement on the bone-rattlers across the border in South Australia.

At Bedourie, a town of perhaps a hundred people, we landed on a fine, wide strip of tarmac that would comfortably take a small jet. According to Ray Mundy, it was all thanks to Sir Jon Bjelke-Petersen, the former Queensland premier. "He built all these nice strips so they'd vote for him," he said.

Bedourie gives its name to the "Bedourie Shower," a red dust storm, but it was rain and not dust that smeared across the windscreen as we took off for Boulia, our last stop for the day. The land below was deeply furrowed with creeks that wandered drunkenly across the earth. This was the Channel Country, named for the writhing mass of watercourses that carry the runoff toward Lake Eyre, the sump of the outback.

We arrived at Boulia just as the first raindrops hit the ground, kicking up little spurts of red dust. Boulia consists of a main street 50 yards wide, 40 houses, a bank, the Min Min Grocery Store and the Australia Hotel. People on outlying stations would think nothing of driving 300 miles to get here.

Home for mail-plane passengers is the Australia Hotel, which is comfortable but nothing fancy. The menu at the hotel doesn't change much: steak, sausages and eggs, three times a day. There's a slight variation at breakfast, when you can have your white bread toasted. In the pilot's notes, under "Hazards," it says "Nightlife in Boulia," but this is a jaundiced view. The cowboys in the bar of the hotel are good for a yarn, especially when they have a city slicker for an audience. Ask them about the Min Min Light, an eerie glow that sometimes appears in the night sky and follows terrified travelers for great distances across the desert.

One of them had hit a kangaroo -- a common accident -- and destroyed the front of his car. He had filled out an insurance claim, but there was no provision on the form for colliding with a kangaroo. "The closest thing was a pedestrian incident, so I put that instead. Then the next question was, 'What happened to the pedestrian?' so I wrote, 'I could see that he was badly injured and probably wouldn't recover so I got out my rifle and shot him through the head.' "

We left Boulia early the next morning and began the long, slow southwestern arc that would take us back to Port Augusta.

When we landed at Sandringham, a 1,700-square-mile Kidman property on the edge of the Simpson Desert, we were met by the manager, Geoff Schroder, a tall, leathery man wearing spurs. Ray's 17-year-old brother was coming to Sandringham soon to work as a jackeroo, a trainee station hand. All the properties here have trouble getting jackeroos, and for about $200 in the hand for a week of dawn-to-dusk toil, it's not hard to see why. Ray had been asking around for weeks, and the word on Sandringham was that it was a good property and Schroder was a good boss, as well as a champion horseman in a country where it still counts.

"What'll he need to bring?" Ray asked now. There was a longish pause while Geoff chopped at the ground with his spurs. "A hat. Yeah, tell him to bring a hat. And a swag {bedroll}. He'll be camping out a bit." For a teenager straight from Melbourne, it was going to be a shock. "Can he ride a horse?" Geoff asked as we turned to go. "No," said Ray, and the crow's-feet at the corners of Geoff's eyes creased as he smiled.

Just before midday we landed at Birdsville to refuel, and Simon grinned at us as we entered the hotel. He was still sitting at the bar with one hand wrapped around a beer bottle, exactly the same as the day before, except that he'd taken his hat off. "The rain set in so I thought I might as well stay a while," he said.

All that afternoon we followed the Birdsville Track south across the desert. The strip at Dulkaninna, the last mail drop before the refueling stop at Leigh Creek, was covered in water, so we left the mail with their nearest neighbors at Etadunna. The airstrip at Etadunna was outlined with rusty cans placed at regular intervals -- holders for flares that had been used to mark the runway for a Flying Doctor plane's nighttime rescue. To make a flare, you soak a toilet roll in kerosene, stick it in a can, light and retire.

It was late in the afternoon when we landed at Port Augusta. Dark clouds were gathering and as I drove back into town the radio crackled as lightning forked somewhere between me and Adelaide. The storm was heading north, the weatherman said. Simon would just have to wait it out.

Michael Gebicki, a writer based in Sydney, is a contributor to "Fodor's 91 Australia."

WAYS & MEANS

The 2,000-mile Channel Run is Australia's longest mail run. Passengers can go along for the ride for $450 Australian (about $375 U.S.), although those prepared to travel standby can fly for $300 Australian ($250 U.S.). The flights have become quite popular, especially between April and October when temperatures are cooler, so it's a good idea to book tickets at least a month in advance.

Augusta Airways is offering a weekend package that includes the mail run, accommodations and meals (except Sunday night). For $785 Australian (about $650 U.S.), you depart Adelaide late Friday afternoon, stay overnight in Port Augusta, take the mail plane to Boulia, where you spend Saturday night, fly back to Port Augusta for Sunday night and return to Adelaide Monday morning. GETTING THERE: Qantas has flights to Adelaide that connect with its international flights to and from the United States. The current fare from Washington to Adelaide, via Los Angeles and Sydney, is $1,735 round trip. Australia's domestic carriers, Ansett and Air Australia, also fly from major Australian cities to Adelaide. Augusta Airways makes the one-hour flight from Adelaide to Port Augusta three times a week, and there also is bus service on the 200-mile route. WHERE TO STAY: The mail plane leaves Port Augusta early on Saturday mornings and returns on Sunday evenings, so it is necessary to spend Friday and Sunday nights in Port Augusta. The town has a number of motels, including the Augusta Westside Motel, 3 Loudon Rd., Port Augusta West 5700, South Australia, phone 011-86-42-2488; rates are $54 Australian double (about $45 U.S.). This motel is part of the Flag Inn chain; within Australia, reservations can be made toll free by calling (008) 335-0005; in this country, contact Flag International Ltd., 2121 Avenue of the Stars, Suite 1265, Los Angeles, Calif. 90067, 1-800-624-3524 or (213) 277-9037. THE WATER: You can drink the water, but it tastes foul and you will drink alone. Cold beer is universally available and more socially acceptable. INFORMATION: For more information, contact:

Tourism Australia, 2121 Avenue of the Stars, Suite 1200, Los Angeles, Calif. 90067, (213) 552-1988; or Tourism South Australia, same address at Suite 1210, (213) 552-2821.

Australian Tourist Commission, 489 Fifth Ave., 31st Floor, New York, N.Y. 10017, (212) 687-6300.

Augusta Airways, P.O. Box 1756, Port Augusta, S.A. 5700, Australia, phone 011-6186-423-100. -- Michael Gebicki