Economics 101--strange science.

FOR many years, Leonard Silk was the chief economics correspondent of The New York Times and kind of a hero for me because of how well he explained the dismal science to non-dismal types. In his primer, "Economics in Plain English," he notes, "This book is based on the proposition that every major idea of economics can be simply expressed."

So Mr. Silk proceeds to take us by the hand and introduce Adam Smith and Karl Marx--as well as to explain business cycles, monopolies and aggregate demand. A trim 238 pages, it's concise, informative, impartial--even witty at times.

Sadly, it's also out of date. Written in 1978 and updated eight years later, my copy of "Economics in Plain English" offers little to explain today's cock-eyed economic scene of irrational markets and jittery CEOs and lost productivity and sleight-of-hand accounting and, perhaps most of all, of lost expectations.

These should not be bad times--not with gross domestic product running at a 4 percent annual rate. Add to that a recent boost in consumer confidence, still super-low interest rates and inflation that, despite $35 steaks and $2.25-a-gallon gas, pales next to the double-digit nightmares of nearly three decades ago. If Leonard Silk were still alive, he might point to this period as an upswing in the business cycle, a time for companies to invest with new plants and employees--and for markets to respond accordingly.

Except it's not happening. True, there's more hiring and a bit more capital investment. True, corporate profits keep increasing. But look at the financial markets: As of last week, the S&P 500 was down 1.62 percent year to date and the Dow was barely staying above 10,000. Is Wall Street bored? Scared?

As you would guess, explanations abound. Corporate earnings may have peaked in the first half of the year, some say, and Wall Street now expects a softer second half. Others point the finger at nervousness over terrorism and Iraq. There also are worries that if John Kerry is elected in November, tax rates for the very rich will be raised above 30 percent (perhaps helping explain Microsoft's one-time, $32 billion payout to investors).

Economics has never been easily predictable, and for all the logic in "Economics in Plain English," there always will be imponderables that muck up the numbers. The old joke of economists opining about "on the one hand this, on the other hand that ..." was first attributed to Harry Truman more than a half-century ago.

But at least in those days there were some dependable rules of the road. Economies overheated, then cooled down, then picked up steam again. Companies had a few good years, then sales slowed and inventories rose, leading to layoffs or plant closings. When business improved, folks were hired back. (That's why they called them "layoffs" and not "firings.")

But now there are very few rules. Recessions can take many forms and impact industries in very different ways. Companies are hiring but workers lack job security and their wages often don't keep up with inflation. Quarterly earnings can show solid gains but investors focus on results many quarters out.

Leonard Silk might find it all too disorienting. But at the end of "Economics in Plain English," he hinted--somewhat ominously--at what was in store. "It is a fact that our industrial society is getting dangerously crowded, complex and putrid," he wrote. "We urgently need a change in social values--a shift in our goals from increasing the quantity of production to improving the quality of life."

Mark Lacter is editor of the Business Journal.