In moments of unusual relevancy, economists wonder how to keep industry going when a few factories can produce embarrassing surpluses of everything. Marketing experts have experimented with several methods, most of them relying on vanity. Airport shops sell prestigiously useless things, like simulated alligator golf bags with the owner's, or somebody's, coat of arms embossed on them. Clever advertising persuades the customer that he wants a golf bag made from a vinyl alligator. Left to himself, he might think the idea ridiculous. Last, the manufacturer convinces him that he must buy a new bag yearly or be sneered at by the neighbors. All of this is socially commendable, keeping two factories and an ad agency open.

A refinement relies on the masculine fascination with equipment -- not equipment for any purpose it might have, but equipment for its own sake. If a gadget has at least two moving parts and a dial, all normal men will want one. Never mind what it does. The owner will probably hang it on a pegboard in the garage, with the saber saw and the set of 300 Allen wrenches, and talk about it with the neighbor. Women are different. They expect equipment to do something or they want no part of it.

For marketers, the separation of equipment from its purpose is a great conceptual advance. The demand for gadgets that fill a need is limited, because the number of reasonable needs if limited. Equipment for its own sake can be accumulated forever. Consider cameras. Few men need anything more than an instant camera. A $20 pocket model is adequate for recording the children plastering birthday cake on the family dog, or the approximate appearance of the new baby. You don't sell a man $3,000 worth of Japanese optics by telling him that it takes pictures.

Instead, you show the thing as a gleaming, pleasantly heavy, button-encrusted, computerized and thoroughly mysterious machine -- editorially pretending that it is intended to take photographs. The ad should show the intricate gizmo against the lucent orange of a South Pacific sunset, or maybe the Crab Nebula. What a man really wants is not a camera. It is something more like a starship. The associated copy must be full of runic incantations about center-weighted CdS meters, aperture priority and flash coupling.

Shop talk is important. The male, for reasons deep but hard to articulate, loves to talk about parts -- parts of anything, as long as they are numerous and complicated. A woman won't. She may know about the parts, or may have designed the parts, but she doesn't want to talk about them. A woman wants parts to have a purpose. A man wants parts.

The marketer's next (and crucial) step is to found a magazine to talk endless shop, aggravating the hapless fellow's gadget fetish and, incidentally, holding the latest equipment before his now-fevered eyes. No more is necessary. Without further urging, he will desire to "upgrade" his photographic "system." Never mind that he can barely take a recognizable picture and probably will never learn. The lust for buttons is a competitive instinct. He will want his buttons to be more complicated and expensive than his neighbor's. Soon he equates his standing in the universe with the complexity of his camera. Its purpose is forgotten: On meeting, photography buffs compare cameras, not pictures. They may not have pictures.

Many industries rely heavily on the equipment arms race -- scuba gear, skateboards, hot-rod supplies. Some, like the stereo business, couldn't survive without it. Stereo magazines devote themselves not to music, but to technical minutiae on the latest and most powerful amplifier. Some of these produce hundreds of watts per channel and begin to resemble small arc welders: wattage is the megatonnage of the "audiophile." The shop talk is lush with power bandwidths, intermodulation curves, harmonic distortion. Sometimes it amounts to another language. One amplifier is said to be ideal "for bridging to attain high-power output for use with subwoofers or bi-amping in a building-block type supersystem."

It has nothing to do with music, and even suggests unfamilarity with music. The sensible way to buy a stereo is to listen to it. If a cheap speaker sounds better to your ear than the $1,100 Krugerhorn Banshee XR, who cares about the Banshee's superior crossover-notch?

Audiophiles care. The terrible truth is that many of them can't tell high-C from the Duke of Wellington, but they like amplifiers. A rational man, if there are any, would buy a superb amplifier and listen to it happily for the next 20 years. But the audiophile hopes and hoards and dreams, so that next year, by selling the car and mortgaging his life insurance, he can get a five-kilowatt Phase-blaster £9K, for listening to his harmonica records.