Readers have been forwarding chain letters to me in great volume lately.

There is so much activity in this field that chain letters appear to have become America's leading growth industry. Postal Service inspectors engage in a modest amount of activity aimed at discouraging chain letters and their organizers, but it is just barely enough to be visible to the naked eye.

The letter I see most frequently these days begins this way: "Looking for new possibilities to raise BIG, BIG legitimate money for Business Capital without borrowing?

"Let Ryan Mann of San Francisco tell you now. This is the fastest plan of them all!!!

I have run these promotional letters five times in the past year. The first time I received $50,000 in cash; the other four times almost $72,000 each time. As a legitimate money-making opportunity seeker, if this letter is continued by you and others, everyone will receive up to $250,000 in business capital FREE."

Well, if everybody can make $250,000 with such ease, I guess the War on Poverty is over and proverty has been annihilated.

The Millionaire's Newsletter, which is also, forwarded to me by a lot of readers deals in even bigger numbers. It speaks of vast wealth in bold face letters, and says that "subscriber John Lewis is reported to be now sitting on $737,888 - all gained in less than five months on a single letter which is enclosed with this tissue of Millionaire's Newsletter."

In smaller type there is also a "legal notice and disclaimer" that says: "The origin of the Millionaire's Newsletter and the accuracy of the facts stated therein are unknown to us. We make no representation as to the authenticity of the statements made, including persons named or amounts of money received."

During its annual Postal Consumer Protection Week in April, the USPS put out a lot of helpful consumer information, including a booklet titled, "There's A Sucker Born Every Minute." Postal inspectors told us how to spot mail order frauds and what to do if we were cheated in spite of our vigilance. But I hunted in vain for a warning about chain letters.

From time to time, readers send me chain letters they have received and ask incredulously, "Is this legal?" Whenever time permits, I check with postal inspectors. But never have I inquired about a specific chain letter and gotten a specific answer. The response is always guarded: "We'll look into it. We try to conduct as many investigations as we can. It takes a long time to develop a case that will stand up in court, you know. We do put a lot of these people out of business but we have to accord them their legal rights."

"But by the time you shut down one operation, they have begun two others with part of the profits," I point out.

"Oh, yes," the inspector concedes. "They do move around pretty fast."

If you inquire whether a specific chain letter is illegal, he will ask you to send him a copy so that he can study it. He has already seen 100 copies of that letter, but no matter. You send him Number 101 - and that's usually the last you hear about it. One gets the impression that laws against chain letters are not very strong, and enforcement is not very effective.

The basic theory behind chain letters is that if we all send each other some money, we will all become rich overnight. Not by working or creating new wealth, but simply by shifting money from one set of pockets to another, we can become a nation of millionaires.

I see no need to comment on the absurdity of such a notion, but I do have one question to ask: When everybody becomes a millionaire, where are we going to find people willing to perform such tasks as milking cows, making clothing, fighting fires, delivering babies or writing newspaper articles? I'm not sure I'm going to like an era in which nobody is under economic pressure to contribute something of value to society.