One of the fastest-growing sectors in the U.S. economy is that of businesses owned by women. The number of self-employed women grew by 74 percent between 1974 and 1984, partly in response to a hostile corporate environment, out of pure entrepreneurial desire and as a result of a better business climate for women. Women went into business for themselves at three times the rate that men did.

More than 90 percent of them are involved in sole proprietorships, and more than 90 percent of these are in service industries -- retail trade, finance, insurance and real estate. While their receipts are relatively low -- the 28 percent of all sole proprietorships owned by women accounted for less than 12 percent of all gross receipts in that sector in 1983 -- the receipts have been growing much more rapidly than the average. From 1982 to 1983, receipts of women-owned businesses grew by 26 percent, as opposed to 6 percent for all businesses that are run by one owner -- man or woman.

Valerie Bohigian, a writer specializing in business, has written a book about the characteristics of women who are able to go into business and make real money at it -- at least $50,000 a year. Many of the women who star in the book make substantially more. The book is entitled "Ladybucks, Why Certain Women Turn Work into Wealth." The term "ladybucks" will be annoying to anyone who believes the dictionary provides an ample assortment of words to use. That shortcoming aside, the book is full of anecdotes about women who have succeeded in business -- and why. And women who failed in certain schemes -- and why. Anyone, male or female, who is hitting a midlife crisis and thinking seriously of chucking the corporate world and starting a business would do well to put the caper off a day and read Bohigian's book. Being in business for yourself can be brutal, and the author pulls no punches.

Hard work, she writes, is "the dullest but truest of all the money-making methods. All hard workers don't reap ladybucks, but all ladybucks earners are hard workers. They put in the hours, tolerate the tedium, plug along and persist." Failure is common: Only 20 percent of all new businesses are in existence five years later.

Although the majority of women succeeding in business now have college degrees, it is by no means a prerequisite for success. Cookie queen Debbi Fields does not have a degree and is running an operation that grosses $70 million a year. "Roberta Williams, head of the $10 million Sierra On-Line software company, devised space-age fantasy games that thrill a generation of children without ever setting foot into a four-year institution.

"The real nuts and bolts of moneymaking can't be learned in a classroom," Bohigian writes. "The intelligence that relates to moneymaking is a particular kind of intelligence. It is street smarts; it is the ability to size up people; it is the ability to influence and impress customers and clients."

Many of those who succeed, she writes, are people "who sense small but significant wants and needs in the marketplace, develop businesses and careers around them, and nourish these niches into riches." Among the examples she cites are Joan Barnes, founder of Gymboree, who capitalized on the exercise craze by adapting it to toddlers.

Then there is Lane Nemeth, founder of Discovery Toys, who was undercapitalized, at one point paying 27.5 percent interest, and who at another point, after the bank refused her a loan in spite of her good credit, refused to leave the building and threatened to call the local media. She got a loan, and then her computer broke down at Christmas time and thousands of orders weren't filled. Disaster loomed at every turn, but today Discovery Toys is a $40 million business.

Bohigian puts to rest some myths about successful entrepreneurs, one of them being that their fortunes are founded on some new idea. "There are very few novel ideas around that dozens of women haven't already discovered, acted upon, and, in many cases, found unprofitable. Usually, if anything, the ladybucks earner gives a novel twist to an old idea -- such as Debbi Fields' selling of warm, just-baked cookies."

The one thing they have in common, she finds, "is a consistent, unebbing wealth of energy." Some wanted careers, some were more interested in motherhood, some wanted to combine both. These success stories are happening throughout the country to women of all ages. They are inspirational, delightful and cautionary tales, and for anyone thinking of taking the plunge, there is a quiz to help you decide if you have what it takes.