WHEN I broke up last summer with the woman I had been seeing, a secondary casualty was the car-camping trip along the coast of Maine we had planned for September. I found myself with ten days of vacation and a feeling of abandonment. In an impulse I called up the Washington office of the Sierra Club and asked them to send me a list of their backpacking trips. I would lick my wounds in the tranquility of the woods. I had done no camping in years, and the little before that had been within earshot of a highway and close enough to a 7-11 to get more ice before the beer got warm. But a friend had recently shown me his slides of a backpacking trip to the Rocky Mountains and the rugged, back-to-basics life they portrayed appealed to me. I saw images of mountain meadows, smiling, tanned hikers, a clear stream bordered by blue wildflowers. It looked quiet and elemental and wholesome. It never occurred to me it could also be dangerous.

The Sierra Club promptly sent me a long list of trips and I chose one simply because it fitted my scheduled vacation: Eight days hiking around the Sierra Nevadas in southern California in the Goddard Mountain area of the Kings Canyon National Park. The trip was rated medium difficulty by the Sierra Club standards, meaning it covered 35-50 miles over a week's time. It had a limit of 14 hikers and there would be two leaders. The cost was $155 plus $25 to join the club, food and cooking utensils included. I sent in the deposit, gathered the equipment listed, and started jogging again through Rock Creek Park.

Having waited until the last possible moment to make travel arrangements, I had to take what I could get. I flew from Washington to Reno, boarded a bus at midnight, and arrived at 4 a.m. in the resort town of Bishop, where the group was to meet.

Disoriented from crossing three time zones, stiff-necked from trying to sleep sitting upright, I walked down the deserted main street of the town in the middle of the night under more stars than I had ever seen before. I could not see the landscape, but I could sense its scale. The air was thin, clean, and cool; and the wind against my cheek, though not blowing hard, felt as though it had come a thousand miles to arrive and would travel another thousand before it hit anything big enough to slow it down.

In the middle of town I found the ranger station where the group was to meet and unrolled my sleeping bag on the lawn. The police may lock me up, I thought to myself as I snuggled down into my bag, but first they'll have to wake me up.

Four hours later I woke suddenly to a semicircle of 15 perfect strangers standing around me exchanging amused looks. A middle-aged man in a bright orange hat with a white feather in it squatted down to my eye level. "Hi there," he said. "For a while we thought you'd stopped breathing."

I got up, stuffed my sleeping bag into its sack, strapped it to my pack, and threw the pack into the back of one of the two vans already full of equipment. Off we went amid a flurry of introductions. The trip had started.

Day 1. At the roadhead all 16 of our packs are weighed to make sure they are within limits; 25 pounds personal gear including tent and sleeping bag, for we will each receive 20 more pounds of "commissary": heaps of group food, pots and pans, bottles of kerosene and white gas for the three tiny stoves, medical and repair kits.

I am three pounds over. I lay aside a jar of Ben Gay, deodorant, and a tiny container of baby powder. Not enough. I take out a pad of note paper, pen, and an ace bandage. There should be one in the medical kit anyway. Still not enough. I dig out a pair of clean socks, underwear, my comb. I break my bar of soap in two. Enough.

Hoisting my pack onto my back, I adjust the shoulder straps and cinch the waistband tight, so most of the weight rides on my hips. It hurts Muscles previously unarticulated in my back spring into painful definition. We start up the trail to the pass, elevation 11,800 feet.

The sun is brilliant but the air is cold and there is simply not enough oxygen in it. I fight off the dizziness and try to settle into a rhythm. Almost moon-like in their starkness, jagged mountains loom up gray on both sides and a few gnarled pines guard tiny blue lakes carved out by the glaciers ten thousand years ago. The trail runs next to a stream and is simply one of its earlier paths, six miles of broken rock.

We are 16, but only the person ahead and the one behind intrude into my thoughts. No one speaks. We keep our eyes on the ground. Each step is a decision. On top of that rock or next to it? Is that one anchored or will it roll and twist your ankle? In less that an hour four coats of waterproofing are scuffed completely from my boots, exposing the raw leather beneath. To my utter horror, the television jingle for Rice-aroni noodles plays ceaselessly in my head. "Rice-aroni (step) The San Francisco treat (step) Rice-aroni (step) The flavor can't be beat (step)." Wen, after twenty minutes, I resign myself to it, it vanishes. I wonder to myself whether, like a disease, it has passed to the hiker behind me.

After two more hours we run into a forest ranger wearing a battered hard hat with a miner's light on it. He is eager to talk. Within ten minutes he reveals: that he is personally responsible for 250 square miles of park, that he makes $17,400 a year, that in his 12 years with the Forest Service he has worked in every national forest west of the Mississippi, that his wife and two young sons live in a trailer in a town some 30 miles away, and that last year he went on 17 search and rescue missions in these mountains. Last month, he tells us, a scout master leading a troop of 10 died of cardiopulmonary complications as a result of coming up to this altitude too fast. "We tried to chopper him out," he says, "but he perished."

This otherwise blunt man's resorting to a euphemism like "perished" immediately strikes me and places him in the company of cops, surgeons, and all those who must accept death as part of their jobs.

Six hours after starting out we make camp just over the pass. I am exhausted from the climb, dizzy and nauseous from the lack of oxygen. There is not enough dirt to anchor the tent pegs, so my tentmate Craig and I tie the lines to rocks. My head swims. I try to vomit but cannot. I crawl into the tent and lie down. I notice that I am shivering and cannot stop.

Craig runs for Wes, our group leader, who tells me I have come down with hypothermia. "Probably got chilled in the wind coming through the pass," he explains while wrapping me in two sleeping bags. "Your body temperature drops and you're just too beat to get it back up. Shivering is just the body's way of letting you know. Not much fun though, is it? You just take it easy."

I lie obediently in the dark while he gives me aspirin and hot sugary tea. Unable to eat, I stay in the tent during dinner. Less than 30 hours removed from my home off Dupont Circle, I find myself immobile and helpless on a trip I have undertaken of my own volition. The ridiculous tent is too small for one person, let alone two. And a flimsy sixteenth of an inch of nylon is the only thing between me and an endless wilderness which could not possibly care less what happens to me. Should I freeze during the night, the birds will sing just as gladly as ever when the sun comes up.

Later Craig tells me that Wes has said to come get him if I start to cough during the night, for it likely means that my lungs have started to fill with fluid. In such cases a person must be gotten to a lower altitude immediately or death may result. I am glad no one has told me about it beforehand.

Day 2. I am still weak, but much better. I wear my sleeping bag to breakfast like a huge shawl against the morning frost and make myself eat as much oatmeal and bacon as I can. Though the day's hike is downhill, it is still eight miles. Weeks of jogging around the city have gotten me in shape to jog around the city, but not to haul a loaded pack over a rocky trail. Cene (pronounced Seenee), a tiny middle-aged pediatrician from Rochester, N.Y., offers to take a few pounds of commissary from my load. Embarrassed by the generosity emanating from the blue eyes behind her thick glasses, I protest but am grateful. The cloth bags of commissary gear are weighed judiciously each morning on a hand-held scale, and it is already clear to each of us that there is no greater favor up here than to lighten another's load. Cene cannot weigh more than 110 pounds and now carries close to 50 more on her back. She walks near the end of our spread-out group, but it appears to be out of preference rather than weakness.

During the camaraderie of supper and sunset, trying to make friends with her, I ask if she has any children. "No," she says, and moves toward the stream to wash her cup. End of conversation.

Day 4. I sit by a stream at noon on top of five identical granite slabs, a tipped-over stack of toast. The sun is warm and gorgeous and I partake of it almost like a drug, but the moment a cloud passes a chill descends, dark and ominous. The roaring white stream is perhaps eight feet wide and impossible to cross without ropes and a stick to hold onto. It is so cold that when I dumped a cupful over my head earlier I nearly lost my footing on the rocks and fell in. There are sleek trout in its pools, hanging almost motionless but for their waving fins until they dart for insects or bits of leaves on the surface. My tentmate Craig fishes for them with an intensity that causes him to lose track of the time, returning to a cold dinner we have put aside for him. He has just passed the bar exam after spending a solid year studying. In six weeks he starts as an attorney with a firm in San Diego. He gives me a rainbow fried in margarine and shows me how to eat it, holding it by the head and tail, like an ear of corn. On a dare he pops one of the eyes into his mouth and swallows it with a crazed smile. "You ever study a whole year for one exam?" he asks.

Day 5. By slowing down and pacing myself, I can actually enjoy the day's travel, the steady progress towards a goal. I prefer walking alone, often near Cene, whose example reminds me that the hike is a process to be savored rather than a contest to be won. The terrain forces my eyes to concentrate on the ground before me, but sometimes when I look around I can sense the unspeakable power of the earth which has thrust these mountains up through its skin like so many fractured bones. This is a raw land of rock and rubble, and I imagine the roots of the pine trees as claws digging through the thin soil to cleave to the rocks beneath.

I eat hungrily and often will spoon and pocket knife for silverware and metal cup for china. For trout or large helpings I eat from my frisbee. I have developed a special fondness for instant coffee, powdered milk, and hot chocolate all mixed together in generous proportions. It's a different kind of eating than I am used to. The object is not satiation, but replenishment of what's been used up. I am sure I'm eating well over twice what I would at home, but if anything, I am losing weight.

Day 6. Two good things are happening at once. I am getting stronger and our packs are getting lighter as the food gets eaten. The day's hike tires me, but it is a healthy tiredness and the day no longer takes me to the limits of my strength. I am proud of myself, I could even help pack somebody else out if an emergency arose.

My pack is starting to feel like a part of my body; there is even a passing feeling of imbalance when it is taken off after several hours. It contains the essentials: dry clothing, food, shelter, fire, light, and something to read until whatever is wrong blows over. Folded into a sack the size of a large loaf of bread is my orange hotel, my tent. Inside it with the door zipped shut, the wind cannot get at me. With the rain fly erected and a little trench dug around the perimeter, I can stay dry in a storm. It traps warmth, too, and unziping it in the morning lets in air 10-15 degrees colder than inside. Scarcely large enough to sit up in, it can hold all my thoughts and still have room for my thoughts. The last thing done each night is to make sure that everything that cannot stand the frost is inside.

Day 8. Last day. Four miles up to Piute Pass and six down to the road. We gather at breakfast and take turns taking pictures of the group. The trail is a straight shot back and there is no danger of getting lost, so people wander off in ones and twos with Wes bringing up the rear. We walsk slowly back to our cities and our jobs, trying to stretch this last day out as far as possible.

In the bright sun and wind of the pass we stop for our last meal and run into a group on its way into the basin. They are new and well-scrubbed and look at our jaunty grubbiness with some envy.

It has been a strenuous, rewarding journey for me, and the 52 linear miles covered belie the distance. I feel I have traveled. I feel as though I have discovered another side of myself, my nearly identical twin, and found him to be a stranger, more vivid, more likable fellow than I ever would have imagined.

It is a gift of nature that the memory of pain fades quickly; and 20 hours later, asleep in my own bed in my own house, memory is already at work erasing recollections of blisters and cold and replacing them with sunrise over mountain ridges and trout hanging motionless in pools.