Gloom and doom is a best seller: for weeks now, Ravi Batra's ''The Great Depression of 1990'' has been near the top of the hardcover nonfiction list, intended to panic you into such total belief in the inevitability of cycles that you will take refuge in cash and gold coins.

This week, The New Yorker features a less exotic, but thoroughly downbeat piece by Robert Heilbroner called ''Hard Times.''

Now comes international economist Stephen Marris, who tells us that the world faces an ''unpleasant'' recession around election time in the United States next year, unless the big powers change their economic policies. And he sees no such shifts coming.

The symbol and symptom of the Heilbroner-Marris anxiety is the huge American trade deficit and its seeming intractability. Since 1980, annual volume of American exports has dropped 16 percent, while import volume has increased 60 percent. Clearly, that can't go on forever.

Marris' account deserves special attention, which it will get during the annual World Bank and International Monetary Fund meetings here later this month. For nearly 30 years Marris was the director of research for the Organization of Economic Cooperation and Development in Paris, keeping a cynical eye on the politicians making economic policy.

In December 1985, he produced a landmark report for the Institute for International Economics, predicting a sharp fall in the dollar, followed later by a recession in the United States. His projections for the dollar slide were uncannily accurate. So far, as he is the first to admit, the recession has yet to show up. But his scenario called for the bottom to fall out 3 1/2 years after the dollar started going down, or around October 1988.

Heilbroner and Marris are not alone. New World Bank and International Finance Corp. reports offer a negative view of global economic prospects -- to be sure, in more cautious, bureaucratic language. The IMF's annual report, published to-day, reiterates that agency's long-standing belief that the huge U.S. trade deficit is not sustainable. It echoes Marris' pleas that the Americans cut their budget deficit, while the Germans and Japanese stimulate their economies.

This is the same music Treasury Secretary James A. Baker III has been playing over the past 30 months. But nothing much happens as a political response: German economic performance disappoints, but no new fiscal stimulative actions are authorized. A hoped-for nudge from tax reform in Japan hasn't happened. Barring a miracle, next year's U.S. budget deficit will be rising again.

Thus, as the dollar continued to fall early this year, the Reagan administration shifted policy. Fearful that a further drop would touch off an inflationary spiral and -- even worse -- lead to a halt in the flow of investment money here, Baker stopped ''talking the dollar down.'' And the Federal Reserve Board started pushing interest rates up, even though the economy was weak.

With his opposite numbers of the Group of Six at the Louvre in February calling for stability, Baker secretly agreed that the exchange rates then prevailing would be defended.

But a pretty price has been paid for this agreement to try to stabilize exchange rates. A useful part of Marris' update of his original study shows that the huge interventions by foreign central banks to prop up the dollar (by buying it when it weakens) boosted their reserves by a phenomenal $73 billion in the first five months of this year. That threatens excessive money-supply creation, especially in Europe and Japan.

What we have seen, in other words, is a desperate attempt by the United States and its major political partners to manage the world's currency system at what is probably an unsustainable level of the dollar.

Why are they doing it? Marris postulates that Reagan is trying to buy time, hoping to postpone an economic collapse until after the election. And foreign central banks, with huge dollar investments, are hoping to keep the system afloat, meanwhile delaying the time when they will have to shift from their comfortable export-oriented trade surpluses to the hard slog of improving their own economies.

Some Wall Street analysts don't think Baker & Co. can continue to play the game this way. They think the dollar will have to be allowed to drop much lower. C. Fred Bergsten, director of the institute that published Marris' study, calls for a further 20 percent decline, say to 115 yen and 1.50 marks to the dollar.

But that, both Bergsten and Marris agree, could precipitate an inflationary recession by driving up the price of imported goods. And there are no guarantees on what such rates would do to the trade balances. So Marris calls it a no-win situation. The world economy, he says soberly, is perched precariously on ''a fragile balance of terror.''

If he's right, one wonders why anyone in his right mind would want to move into the Oval Office in January 1989.