July 9, 1995

Past performance, as the prospectuses say, is no guarantee of the future. But if you understand what produced the results, it can help in forecasting. Nowhere is that more clear than when a small mutual fund has got hot. It pays to learn not just the percentage gains the fund has racked up, but to figure out how many dollars were involved, and what investment decisions really produced the gains. Maybe the manager was good; maybe lucky. But if a fund has grown rapidly, a strategy that once worked may be impossible to repeat, a fact that many investors learn only after they have leaped into the fund.

The United Nations force in Bosnia has only a few weeks left to prove its effectiveness before a costly and dangerous NATO withdrawal of the United Nations soldiers -- involving as many as 25,000 American ground troops -- is almost certain to begin, officials on both sides of the Atlantic say. Both President Clinton and allied European leaders are making new efforts to support the embattled peacekeeping force and insist that they have not given up hope.

THE stock market has zoomed skyward this year, with the major stock indexes all up more than 20 percent since the end of 1994. The Dow Jones industrial average topped 4,600 for the first time ever on Wednesday, and then exceeded 4,700 just two days later. And this move is just continuing a bull market that erupted 13 years ago. If you've owned stocks for much of that period, you've probably done better than you ever dreamed possible. You may also be getting a bit nervous. Can such good things last forever? Should you take some of your chips off the table? And if so, how?

Sale prices for at least one type of New York City co-op -- ultra-luxury, high-end properties -- have finally climbed back to, and in some cases now exceed, the peak of the market in the late 80's, according to Lawrence Sicular & Associates, an appraiser and researcher in Manhattan that surveyed 41 apartments that sold for at least $3 million in 1994 through mid-May. "It's a fairly small universe," Mr. Sicular said, noting that because of the low number of apartments in the study he was not able to calculate a median sales price for this rarefied niche or an overall percentage increase over the last five or six years.

THE ENGINE OF REASON, THE SEAT OF THE SOUL A Philosophical Journey Into the Brain. By Paul M. Churchland. Illustrated. 329 pp. Cambridge, Mass.: A Bradford Book/The MIT Press. $29.95.