IF YOU WANT a soothing antidote to those scary headlines that warn us each morning of impending nuclear holocaust, economic collapse, terrorism, crime in the streets, and the end of the world--Encounters With the Future is the book for you.

This forecast of how the world will be twenty-some years from now looks beyond the headlines, at the underlying social, technological and political changes that are shaping our lives. And the authors see a brighter, less dangerous, wealthier future ahead.

Dr. Marvin Cetron, president of Forecasting International, claims accurate predictions of the Solidarity strikes in Poland, the revolution in Iran, the Arab oil embargo of 1973, among others. Thomas O'Toole, space and science correspondent for The Washington Post, has won numerous awards for his reporting and writing.

What will the world be like in the year 2000? The authors foresee, "The majority of us will be better off . . . than we are today. We'll feel better, we'll look better, and we'll live longer." They find an 8 percent inflation rate out to the year 2000 is "acceptable," with interest rates stabilizing at 11 percent. "There will also be fewer billionaires, but that will be the result of tax reform." Taxes will generally go down, stock prices up, robots will take over the factories and fusion power will end the energy crisis forever.

There will be no major nuclear war, although a few second-rate powers such as Pakistan or Argentina might lob a nuke or two at unfriendly neighbors. (The authors, writing well beyond the current Falkland Islands crisis, present a scenario in which Argentina attacks Brazil with nuclear weapons.) In America, the position of women in industry and politics will steadily improve. There will be medicines to improve and restore memory, pills that cure phobias such as fear of heights, drugs to keep men from going bald and women from turning gray.

Society will become cashless and checkless as computers and credit cards take over completely. The Roman Catholic Church will slowly change its opposition to birth control and divorce. Germany will be reunified, and the Cold War will subside. Even the Middle East will calm down as Israel and its Arab neighbors learn that they have more to gain from cooperation than from war.

That's the good news. The authors claim that each of the predictions is solidly based on trends and data that they have uncovered. They present a believable set of forecasts and back them up with impressive credentials and research.

Then why does the reader get the uneasy feeling that this is all too good to be true? For two reasons.

First, no matter how well-founded the forecasts may be in factual data, they do not take into account the human factors that actually drive history. The Israelis and the Arabs have known for 30 years or more that they have more to gain from cooperation than from war, yet they still do not cooperate. They do not trust one another, and they will not trust one another over the next 20 years--not as long as they continue to kill and terrorize each other. Tax reform and welfare reform in the United States is a laudable goal, but neither the very rich nor the very poor will support such goals. Indeed, both sides will do their best to perpetuate the system we have now, and save their best energies for carving out a little more for themselves, at the expense of every other segment of society.

Secondly, there is a basic flaw in this method of forecasting. When one attempts to predict the future by measuring and extrapolating past and current trends, it is rather like trying to drive an automobile by staring fixedly into the rear-view mirror. Can we really judge where we are heading by looking carefully at where we have been? The answer is a guarded yes; it is possible, but only to a degree. There will be unexpected bumps on the road that the rear-view mirror cannot warn us of.

Forecasters, especially when they bite off such a huge chunk of the future as the whole world for the next 20 years, are likely to miss a few morsels. There are connections between one set of predictions and another that gets missed. For example, in discussing the huge amounts of energy the average American consumes, the authors overlook entirely the fact that our energy consumption has a direct relationship to our individual freedom. Ration gasoline, and we cannot travel as freely as we do today. Living with less electricity would restrict our lives enormously.

In a book of this scope, it is inevitable that a few minor errors and inconsistencies crop up. For example, the authors are apparently unaware that human growth hormone is being used in the United States to treat dwarfism, or that the Department of Energy has thrown in the towel on the electric car--for which the authors have high hopes.

On one page, the authors claim that the United States "has become depression-proof," yet, seven pages later they warn of "the coming deep recession." On another page, they predict that "the divorce rate among the people who work at home (on computer terminals) will quadruple before the end of the century," while on the very next page they say, "domestic life could be strengthened in the long run" by keeping the family at home.

But these are minor flaws in an otherwise solid, interesting, and entertaining book. If you are seeking guidance on career opportunities or future stock market investments, information about which nations will become stronger over the next 20 years and which will weaken, or simply a reassuring glance at a future that is not doomed to destruction, pick up Encounters With the Future.