When Charles Allmon looks at the booming stock market -- the Dow up 250 percent in five years, new highs being hit on a daily basis, small investors and foreign money pouring in with equal enthusiasm -- he gets a queasy feeling and thinks ... well, let him tell it.

"The whole thing reminds me of the chap who thought he could produce a baby in a month by getting nine women pregnant. People want to get rich quick. I don't mean to be a killjoy, but this thing has simply gotten ahead of itself ... There's no other business in the whole world where the customers will not buy the merchandise until it's marked up 200 percent."

Allmon isn't the only money manager mystified by the market's run-up, but he's one of the few who's acting on his instincts. President of the Bethesda-based Growth Stock Outlook Trust -- a closed-end fund trading on the New York Stock Exchange -- and also a private portfolio manager, Allmon is responsible for $425 million. At the moment, 70 percent of it is in sweet, cool, highly liquid cash.

"Two out of three people coming into the stock market today have never been in stocks in their life. That tells me we're heading for a big crash. This is strictly a speculator's market," he says. "Everyone is hoping to find a bigger fool, and in due course you're going to run out of fools."

Allmon expects the end to occur when the Tokyo stock market collapses, and the Japanese have to pull their money out of Wall Street to cover their losses. His six- to 18-month Dow prediction: 1700 -- a decline of a mere 1000 points. To put it another way, the market's going to suffer a bigger loss than its entire size four years ago.

Yet that's a mere blip compared to what Ravi Batra expects. In three years, Batra figures, there won't even be much of a Dow. From a high of 4,000, it will decline to about 600. Close your eyes and imagine the Bulgarian stock market, and you'll get the scene.

Batra, a professor of economics at Southern Methodist University in Dallas, is author of The Great Depression of 1990 (Simon & Schuster, $17.95). With a quarter-million copies in print, it's one of the hot summer reads. Not bad for a tome that, two years ago, was rejected by 55 publishers with quite forthright letters of refusal (one said it was the worst manuscript on economics he had ever read). Batra ended up publishing the first edition himself and hawking it to local bookstores.

The book's argument is complex, but essentially holds that we are in the tail end of a boom. A wave theorist, the 44-year-old Batra believes it takes two generations for the concentration of inherited wealth to hit a dangerously high level. Then the bubble bursts and we have a depression. The last depression, of course, got rolling in 1930. A host of other convergent cycles leads the author to conclude that a new bust is just around the corner.

In Batra's analysis, the concentration of wealth -- currently, he says, 1 percent of the population has more than a third of the money -- is the cause of all of the economy's problems, including the enormous domestic and foreign debt. Among its arguable consequences:

Since there's only so much money to go around, the poor and middle class have fewer assets. As a result, they're forced to borrow to maintain their constantly threatened standard of living -- the reason why we have such a monstrous consumer debt.

The creditworthiness of the majority of borrowers declines, because they have fewer assets to support their loans. As the profit-hungry banks lend money to credit-risky people, the financial system becomes very shaky.

The wealthy, who can afford to gamble with their money, start speculating on the stock market. Historically, Batra argues, most stock market booms have lasted seven years. (The current rally, remember, just had its fifth birthday.) The rise in stocks, meanwhile, feeds the concentration of wealth, creating a circle and fueling the disaster.

The one way to avoid Batra's coming depression would be to radically redistribute wealth. "There's no other business in the whole world where the customers will not buy the merchandise until it's marked up 200 percent." -- Money manager Charles Allmon This is about as likely as Congress and President Reagan succeeding in balancing the budget. Nevertheless Batra, who's accumulating a nice concentration of wealth himself with his book sales, plans to devote part of his funds to start a "wealth tax" movement called Stop the Coming Depression. Another slice of his pie, he promises, is "going into a trust fund, to feed the hungry in the 1990s."

The Great Depression of 1990, while getting mixed notices, is nevertheless being treated seriously by reviewers -- "provocative" is a favorite word. Batra provides a number of intriguing parallels between the '20s and the '80s -- in both 1926 and 1986, for example, stocks broke another record, bank failures increased, energy prices fell, and tax reform reduced rates for individuals while raising them for corporations. And both decades, he predicts, will end the same way.

Yet Charles Allmon -- even if he expects a market collapse sooner than Batra -- will have nothing to do with the economist's theories. "This guy wants to limit top incomes -- they could be no greater than ten times the bottom income," says Allmon. "That's absurd. Where does he think the money's going to come from to create jobs if there are no entrepreneurs?"

In Allmon's view, Batra's radical solutions discredit his theories. "He has to eat, and he's going to eat well. But we've always had these potboilers. Paul Erdman wrote The Crash of '79, and that was just nonsense. Harry Browne's advice to go live in the north woods, Howard Ruff saying gold was going to go through the roof ... None of what those doomsters were forecasting ever happened. {Batra} is crying doom all the way to the bank. Would you want him managing your money?"

Actually, despite a superior track record -- GSO Trust has only been in operation for a year, but over the last seven years, Allmon's model portfolio has ranked fifth out of about 30 of those tracked by the Hulbert Financial Digest -- some of his clients have decided they don't want him managing their money, either.

"We expect to lose maybe 4 percent of our managed account clients," he says. Meanwhile, with the GSO Trust shareholders, "a lot get discouraged that we're going no place and we're sitting on all this cash. But we've been making steady progress on a net asset basis."

What these impatient speculators probably want, the 66-year-old Allmon feels, is a "kid."

"If you want to make money, you go out and rent a kid. They're rolling dice with your money. If he loses 50 percent of your capital, he'll lose his job, but you'll lose your capital. For most of these fellows, long-term is between lunch and dinner. I'm talking about five to 10 years."

And by that time, he expects happier days. "This {stock collapse} is not going to destabilize the economy ... I feel optimistic about what's down the road. Sooner or later, we're going to have to live within our means."

Allmon and Batra, then, are mirror opposites. The first expects a short-term blowout and then a longer period of prosperity. The second expects the economy to remain prosperous up until 1989, after which it's into the abyss. It's possible, of course, that neither will be right -- hey, maybe the economy will keep chugging along and the Dow will reach 6,000 by 1995.

At the least, however, both men are remarkably confident. "I'm not a bull or a bear right now, I'm a chicken," says Allmon. "We're getting a piece of the action, but we're always looking over our shoulder ... I'm the single largest shareholder {in GSO Trust}, and I don't plan to lose my shirt."

And Batra? "I will be the happiest man if the depression doesn't come through," he says. "I'll be happy to be proven wrong. But I don't recall ever making a wrong forecast in my life."