Travel and food coexist in a funny kind of equation: The more extreme the former, the more extremely good, or bad, the latter. There seems to be little or no middle ground: Travel hard and far, and what you dine on will either delight or horrify you.

My father, a Chinese food epicure of the highest order, swore that the finest Sinaean dish he ever ate was in an obscure restaurant in Macao, run by the Tongs, that specialized in food for opium addicts: crab meat and ginger, somehow, alchemically, simmered in curdled buffalo milk, into a kind of evanescent froth.

Norman Tinsdale, the great Australian anthropologist, used to wax ecstatic over witchetty grubs, giant fat insect larvae dug out of the earth and eaten raw and wriggling by the Aborigines and their lucky guests in the Outback; he compared it to eating a live ice-cream cone.

The 19th century Plains Indians -- the Dakota, Cheyenne and the rest -- served their friends something called "green buffalo," meat from bison that had drowned in the autumn, been trapped under the river ice all winter and thawed free in the spring.

Ugh, indeed. Or, who knows? Maybe it was delicious, the same way Limburger cheese and sea-urchin sashimi are delicious. If beauty is in the eye of the beholder, taste dwells in the taste buds, and the mind, of the diner; the more one travels, the clearer that fact becomes.

I was once guest of honor at an Akah tribal feast in the hills of northern Thailand, the Golden Triangle, where the pie ce de resistance was fricassee of dog; mighty good it was, too, the meat shredded and quick-fried, along with onions and chilis. The only problem was, my hosts had prepared the entire meal in front of me, beginning with the dispatch and dismemberment of three extremely cute little puppies, who were the main course. Every time I began to enjoy a mouthful of food, those wagging tails, lolling tongues and bright button eyes appeared in my mind's eye, ruining everything.

A photographer friend of mine had a similar experience in Afghanistan, when his Mujahedin guerrilla hosts decided to treat themselves and him to a roast-beef dinner. They managed to find and buy a suitable cow, and get it back to their base camp safely; the problem was, the only killing and carving implements they could come up with were an extremely dull sickle and my friend's Swiss Army knife. Using these unsatisfactory tools, it took several hours to convert the ambulatory meat on the hoof into barbecue material, and by the time the operation had been completed, my friend found he had lost his appetite.

All of which brings up another rule familiar to all traveling diners: Information is the enemy of appetite; food, like sex, benefits from mystery. Or, "Don't tell me what's in the calabash till after I drink it." And, no, I don't want to see the kitchen. Thank you.

There are places on earth where it is well-nigh impossible for a visitor to get a decent meal: These are not necessarily countries with no good food, but ones where, for one socio-cultural reason or another, there is no real tradition of going out to eat good food in public places.

Peshawar, in the Northwest Frontier Province of Pakistan, for instance. I spent a couple of months there this spring, and I never did eat well, outside of a couple of dinners at the homes of friends. Ghastly curries, monstrous parodies of Chinese food, meat the consistency of a huarache sandal, cookies as dry as dust and sweet enough to rot the tusks of a narwhal . . . Even the soft drinks were bad: The local restaurateurs contrived to serve them lukewarm, in unwashed glasses, with nuggets of filthy ice. A meal was a raving success if it didn't send you racing for the Lomotil bottle three or four hours later.

Another bad town for hungry travelers is Kathmandu, otherwise one of the two or three most charming metropolises on earth. Except for the tandoori chicken at the Malla Hotel and the muesli cereal (imported) at the Swiss Restaurant, the place is a gastronomical dead zone. Tibetan dishes like mo-mo (dumplings) and thupka (noodles), which can be delicious, reach almost supernatural nadirs in the hands of Kathmandu chefs; attempts to pull off western favorites like pizza, apple pie and spaghetti produce even worse disasters.

Kathmandu restaurant ambiance is, well, unique: I had one dinner date at the city's third-best hotel interrupted when a monster rat fell out of the ceiling onto the table-top, raced panic-stricken through the Chateaubriand for Two, leapt onto my date's lap, onto the floor, and away.

The primary problem with Kathmandu food is really primary: the ingredients. Meat has often gone bad by the time it reaches the restaurant kitchen -- local refrigeration techniques are dodgy -- and chicken and eggs, formerly a sure bet in the animal protein department, became a total disaster a couple of years ago when some local genius discovered that you could grow birds big, and cheap, feeding them on fish meal. The only problem is, both chicken and egg end up tasting like fish meal, which means they taste like 39 cents-a-can cat food smells. And that's not good. The Malla Hotel must get their chickens from some secret, untarnished source, some place where fish meal chicken-feed never caught on.

You can even go wrong eating out in the best cities: The most disappointing meal I ever ate on the road was in Hong Kong, that most marvelous of restaurant towns, where the finest cooks in China ply their trade at places like the Great Billionaire Restaurant, the Peking (the one in Wan Chai) and Winter Garden.

I had gotten into the habit of lunching at a certain little noodle shop in the Tsimshatsui district of Kowloon, a working-class hole-in-the-wall with a huge array of lovely noodle dishes, icy soft drinks and friendly waiters. Even if I had only 2 1/2 or three hours between planes, the briefest of layovers, I would take a cab on from Kai Tak Airport, hit the noodle shop for a big bowl of congee and another of noodles, and then window-shop the incredible supermarkets of electronic gadgetry before taxiing back to the airport to catch my flight out.

This particular time, I had been in Hong Kong a couple of days, and I decided to celebrate my last lunch (I had an afternoon flight out to Bangkok) by ordering The Special. The Special had always intrigued me: It occupied a boldface box in the middle of the bilingual menu, and it was by far the most expensive thing in the house; it must be, I thought naively, an amazing dish, the Aristotelian ultimate in Chinese noodles.

Since that day, I have evolved two widely divergent theories to explain The Special. Theory number one is that it was first cooked to order under the supervision of a large, inebriated sailor, who was trying to re-create a dish from his native Lower Slobbovia, only he couldn't quite remember the ingredients. The noodle-house proprietors had kept it on the menu ever since in his honor, or in case he returned some day and ordered it again. My second theory is that the dish was invented as a practical joke, to spring on unsuspecting occidentals, and that the Chinese characters next to "The Special" on the menu really said, "BEWARE! Don't Order This Dish!"

There was nary a shred of noodle in The Special: It consisted of a molten sea of fish chowder, mixed with what appeared to be cream of vegetable soup; the sea was ringed by a moat of instant mashed potatoes, and the moat, as well as I can remember, was surmounted by sourdough biscuits. It was the strangest brew ever served up in a Chinese noodle house, and it was enormous. And I had to eat the whole thing: Ordering The Special was evidently a rare and important event, because every waiter in the place gathered around to watch me eat it, smiling benevolently as I spooned up the obtuse stuff. Whenever I hesitated, or slackened my pace, a luminous face would lean down and ask, "You like?" or "Is okay?" Smothered in solicitude, I ate every speck of it, gritting my teeth and stealing longing glances at the delectable dishes being eaten on all sides of me. I still don't know if I was being japed or not; the Mysterious East strikes again.

You don't have to go to the ends of the earth to find dreadful food, of course; any experienced domestic traveler can spin countless tales of horror-show dining on the road. A certain Rocky Mountain airport is my particular nemesis: the surliest waitresses in Christendom, mile-high prices and food that rivals any in existence in repulsiveness. Remember the sausage in Orwell's "Coming Up for Air" that burst in the protagonist's mouth with a taste so vile that it induced a bout of existential despair? Well, I ate that same sausage last month at that airport, and it cost me something like $2.50, which is a lot for a hot dog gone wrong.

And then there was a fast-food restaurant in Tucson, one of a nationwide chain, that once served me a breakfast in which everything solid was square: square block of scrambled eggs, square sausage, square hash-browns (frozen in the middle, charred on the outside) . . . even square biscuits, submerged in a mucilage-like gravy. All of it was awful.

One could write volumes on the badness of airline food, of course; but that would be flogging the proverbial dead horse, long after it has been cooked and served.

And then, of course, there are the meals you encounter Out There that are so good you never forget them: the thick pot au feu at that little Norman inn on a cold winter's afternoon, with long spars of celestial bread; black tea churned with yak butter and salt till it seethed like champagne, in a stone hut below Everest; those fish, less than an hour out of the sea, they broil on the coals at Matachine Bay . . . But that is another story.