There's a small band of genuinely great investors in America--people who made a fortune for themselves through their knowledge, contacts, staff work, imagination and native wit. On Wall Street they are legends in their time: the Belzberg Brothers of Vancouver, Teledyne's Henry Singleton, Berkshire Hathaway's Warren Buffett, oilman Marvin Davis, and David Murdock, one of the largest shareholders in Occidental Petroleum. But beyond the temples of high finance, hardly anybody knows their names.

If you did know them, and what they were doing, could you profit from it? Probably so. That, at least, is the premise of a new biweekly newsletter called Street Smart Investing (P.O. Box 173, Katonah, N.Y. 10536; $195 a year; $48 for three months). Editor Kiril Sokoloff keeps track of the largest stock positions taken by the great investors, and tries to find out what interests them about the companies they buy so heavily.

As soon as any shareholder acquires 5 percent or more of a public company's stock, he has to disclose all purchases and sales of that stock on Form 13-d, filed with the Securities and Exchange Commission. Recently, these forms have been filed at an average of 25 a day.

Sokoloff screens the 13-d's for new moves made by around 100 major investors who, in his opinion, have the best records for sniffing out value. "I use them as my research department," he says. "When they buy, I'm interested." He then investigates the company in question, looking for its investment story. If he finds something going on at the company that makes it a superior value at the price, he tells its story in his newsletter.

Some of the buys become quick turns on takeover situations. The Bass Brothers bought Marathon Oil at $54 and one month later tendered the shares to U.S. Steel for $125. Two months after the Belzbergs bought Pargas at $26 a share, Forstman, Little acquired the company at $42.25.

Some speculations catch the market just right. The New York City real-estate investor, Sol Goldman, bought Alexander's in September 1980, at $7 a share and sold in October at $13 to $14. In the same year, David Murdock bought Faberge at $7 to $10 and sold three weeks later at $14.25.

More often, however, the investors on Sokoloff's list are in for a longer period. It's not unusual for them to double their money in a couple of years.

Do they make mistakes? Sometimes. Two years ago, the Belzbergs bought Revere Copper at $13 and $17. Today, the company is reorganizing under Chapter 11 of the bankruptcy act. But its stock is still selling at $12 3/8, and Bear, Stearns recently bought a major interest. "The final chapter on Revere Copper hasn't yet been written," Sokoloff says. "There's no way they're not going to make money." All told, there are mighty few losers among the companies that these key investors buy so heavily.

Sokoloff's current interests include General Foods (at this writing, selling for around $46 a share) and R. J. Reynolds Industries ($50 7/8), currently being bought by Warren Buffett. Analyst Ed Jones of Paine Webber describes General Foods as an "old-line, bureaucratic company that is rapidly becoming more aggressive." R. J. Reynolds--a leader in tobacco, fruit and vegetable processing, fast-food restaurants, liquor, oil exploration and production, and containerized shipping--has had 13 consecutive years of rising sales and earnings, and has raised its dividend every year since 1971.

White Consolidated ($40), a big conglomerate heavily involved in the booming home-appliance business, was recently bought by Saul Steinberg. Idanta Partners, a San Diego-based venture-capital-oriented firm, bought into an aggressive, new bank called First National Corp.-California ($10). A company controlled by Carl Lindner has been buying Orion Capital ($29 7/8), an insurance holding company which itself has been making some spectacular investments and strategic business decisions.

When you're following the great investors, you have to be willing to move promptly. If you tend to watch a stock rise for six months before buying it, you may find yourself getting into a company just when the investor you're following is getting out.

When word gets out that a well-known investor has bought a small company, the stock may take a sudden jump. But Sokoloff advises clients not to chase the stock price up. "The time to do your buying," he says, "is after the initial flurry has subsided and the stock drifts back to where it was before." And what if it keeps on going up? Leave it alone, he says, and wait for another. There's plenty more where that one came from.