If the first stage of a private company's success is marked by the owner's ability to be paid a decent salary, then the second stage comes when the owner can safely begin to diversify his or her own personal funds. Relying on a stockbroker's sales pitch can be risky; unfortunately, many investment guides run the gamut from incomprehensible to imbecile.

Here are two books that are different -- in large part because each of them provides a wealth of easy-to-comprehend, easy-to-use data on a range of investment options:

*How to Invest $50-$5,000, by Nancy Dunnan (HarperCollins, 1991, $9.95). Don't be fooled by the grade-school title. Few books around can teach people more about the investment universe than this 120-page paperback does with as few wasted words. Dunnan spotlights key issues such as how to choose between tax-exempt unit trusts and tax-exempt bond mutual funds, how to participate directly in U.S. Treasury bond auctions, when it makes sense to purchase an annuity, and so on. If some sections seem too simplistic for your level of investment competence, just skip them; you'll certainly find other sections that will broaden your perspective and improve your ability to evaluate an investment adviser's recommendations.

*The Better World Investment Guide, by Myra Alperson, Alice Tepper Marlin, Jonathan Schorsch, and Rosalyn Will (Prentice Hall, 1991, $19.95). With a focus on socially responsible investing, this 500-plus-page book applies a microscope to the employment, ecological, foreign-investment, and other practices of 100 historically profitable stocks. In 3 or 4 pages of brief corporate descriptions, you'll learn more about those companies than any stockbroker will ever tell you. Other sections of this guide provide useful leads to pension-fund managers and mutual funds.

-- Jill Andresky Fraser