IN THE PAST

week I've turned from a net seller into a net buyer of stocks. My view of the market has turned from cautious to positive. In fact, I haven't felt better about buying stocks since last April 14. Does this sound paradoxical? Does the very idea of buying stocks now make you uneasy? Are you still reeling from all the earnings and revenue warnings and the market's dismal performance in September? Then read on.

Last summer I mentioned in this column that I was cautious about the market and was following a strategy of selling gradually into the market's rise in order to raise my cash level to about 10%. I'd accomplished this by mid-August and, coincidentally, the market's rise ended about Labor Day. The converse of my attempts to sell into rising markets is to buy into declining ones. It's a simple way of putting into practice the old adage of "buy low, sell high." I'd restate that as "buy lower, sell higher."

As I've said before, I don't try to market time. It's impossible to know the future. You can never expect to pick an exact high or low, either for the market as a whole or for individual stocks. If you do, you're simply being lucky. A recent reminder: I didn't think the market would correct in September because everyone I talked to thought it would. My reasoning was that surely everyone would already have sold before September arrived, as I had, if they thought the market would go down. The logic still strikes me as unassailable. But the market did go down. So repeat after me: The market doesn't follow the rules of logic.

Still, it's one thing not to market time and another to buy and sell blindly, without regard for broader market trends. There are better and worse times to buy and sell, and I try to take advantage of these by moving back and forth from being fully invested to about 10% cash. Over long periods of time, that's significantly boosted my performance above what a strict buy-and-hold strategy would have yielded. And even for investors who do buy and hold, you have to buy sometime, and occasionally you need to sell. The same principles apply.

The best time to buy is right after what market professionals refer to as a "selling climax." Selling climaxes are marked by high volume and extreme downward volatility. But more important, in my view, is the way they "feel" to the average investor. And that, in a word, is bad. Not just bad, terrible. You feel like we're on the brink of the next Great Depression. Panic isn't very far over the horizon.

We haven't had a selling climax recently. April 14 was the closest we've had this year. Oct. 8, 1998, came close. In 1987, Oct. 19 and 20 were definitely a selling climax. And, as everyone knows by now, the immediate aftermath was a fabulous time to buy stocks.

It would be ideal, of course, to buy only in the aftermath of selling panics. The trouble is, they don't happen very often. So for more frequent buying opportunities, we have to look for the cousin to the climax, what I call the sell-off. The sell-off also has high volume and steep declines, but it may occur over several days or weeks, and not every sector gets obliterated. Again, the feel of this is important. Despair and pessimism are almost palpable. To me, the market has had the feel of a sell-off during the past week, ever since Intel and then Apple issued warnings.

The important thing is to recognize a selling climax or sell-off and the bad way it makes you feel. However unpleasant they may be, these feelings are an important signal. So get a grip on yourself. Do NOT call your broker or go online to sell stocks. As your panic subsides, it's time to calmly and rationally assess the reasons for the market's decline.

There's always some ostensible reason for a sell-off. Recently, it has been a combination of higher interest rates, high oil prices, the troubled euro, sagging consumer spending, negative earnings surprises from companies thought to be immune from economic vicissitudes and lofty valuations at current stock prices. All of these things are real. But will they persist?

The answer, in my view, is no. It lies within the power of the Fed to cut interest rates, and at some point it will. It certainly isn't going to raise them in this environment. Oil prices will subside at some point, as I argued in a recent column. The euro won't stay down forever. Consumer confidence will revive. And many stock prices have corrected, in some cases drastically.

If you disagree with me, you shouldn't buy at these levels. But if not, you should overcome your emotional aversion to the market and buy something. Bear in mind that I'm not trying to predict where the market will go from here in the short term only that it makes more sense to buy now than it did a month earlier. I always have a list at hand of stocks I want to buy or accumulate that I use at such times.

Except in the rare incidents of a selling climax, I would never commit all my cash at once. Let's hypothesize that the market continues to decline. If I spent 20% of my cash, as I did last week, I force myself to wait for a further 5% decline, and then allow myself to invest 20% of what remains. So I never completely run out of cash. Should the market drop 30% (a pretty severe correction by historical measures), most of my cash will have been committed. Obviously, you can adjust these figures to whatever level of risk makes you comfortable. The important thing is to have a disciplined approach. Otherwise, your emotions will run away with you and with your chance for superior returns.

The Wall Street Journal ran an excellent column not long ago pointing out that a bear market is a long-term investors' friend, especially if you're young, or even relatively young. A bear market simply means that you're buying stocks at ever-greater bargain prices. Someday, remember, the market will resume its rise.

The stocks I invested in last week certainly felt like bargains. They're a veritable rogue's gallery on Wall Street these days: Worldcom, Lucent, Nortel Networks and AT&T. With the exception of Nortel, which I recommended last December, all have recently been discussed in this column. Can they still go down? Of course. Then I'll be ready to buy more.