By now, Sandy Zimmerman's transition from chief executive officer of Abraham & Strauss, a division of Federated Department Stores Inc., to owner of Cohoes Specialty Stores Ltd., the wildly successful discount clothing chain based outside Albany, N.Y., has been touted in headlines and relegated to retail annals. After a 27-year career in department stores, Zimmerman arrived at the top only to find himself so embroiled in corporate politics that he had no time for day-to-day business. In 1979, he decided to go into business for himself, and he has never regretted it since.

Today's boom in specialty shopkeeping is inducing more and more people to follow Zimmerman's example. "Increasing numbers of rising lights in U.S. retailing are bailing out to run their own businesses," says Joseph Carideo, partner with Thorndike Deland Associates, an executive search firm based in New York City. Some, like Zimmerman, feel constrained by the corporate world; others are simply attracted to the challenge of surviving as a smaller retailer.

For Ellen Fine, it was the itch for adventure that made the difference. By the time she was 27, Fine was Bloomingdale's number-one furniture salesperson; she had a nice house in the suburbs, a Peugeot, and a salary of $30,000 a year. "I'd topped out," she says now. "There was no way I could make any more money doing what I was doing." Taking a $20,000 pay cut, Fine moved to the city and enrolled in Bloomingdale's training program for buyers. From there she became the company's bedding buyer, upholstery buyer, and group manager; later, in a rare move, she switched from upholsteries to ready-to-wear clothing, two realms that were traditionally kept separate.

"I liked Bloomingdale's," Fine remembers, "but after a while it's all the same. Was I going to stay there forever, or was I going to try my own business and opt for an adventure?"

In 1983 she plowed $1,500 into Fine Designs, a tiny pushcart business in The Rouse Co.'s New York South Street Seaport marketplace. Her niche: seemingly unrelated products, ranging from -- what else? -- home furnishings to ready-to-wear clothing, all the products related through imaginative color-coordinated designs. Fine's tastes, fine-tuned through her buying experiences, hit the mark: Business boomed and she soon had pushcarts in several Rouse developments, with daily sales reaching into the thousands. Eventually, Rouse offered her a store, and then another; today she owns eight. Bloomingdale's, says Fine, was the key to her success. "I was so used to thinking big that I simply never translated my ideas into anything little. The pushcart was little, but not for a moment did it occur to me that my business was."

For Gary Hoover, the move from big to small was part of a carefully planned, eight-year path through the large retail world. Hoover first went to work as a securities analyst, then became a buyer of books and sporting goods with Sanger-Harris, a Dallas-based division of Federated Department Stores Inc., and later a manager of corporate development with the May Department Stores Co. chain. Finally, working for a May subsidiary, he managed shopping-center developments and learned about real estate.

Meanwhile, Hoover had settled on a plan to open a discount bookstore chain. In 1982, raising about $500,000 through private investors, he opened Bookstop Inc., a large discount bookstore based in Austin, Tex., and modeled after the $2.5-billion Toys 'R' Us specialty chain. Bookstop specializes in selling every kind of book to every sort of reader, at a low price. With 9 locations (12 are planned by Christmas) and sales of more than $10 million, the company is beginning to reflect Hoover's lifelong ambition.

"Retailing is fundamentally simple," says Hoover. "I know what [big retailers] do, because I used to do it myself -- sit up there and use all those fantastic tools for analysis: numbers, computers, spreadsheets." At Bookstop, Hoover is evolving a program in which the entire management staff -- himself included -- work as salesclerks. The big retailers, he says, spend too much time making decisions, weaving through bureaucracies.

Which isn't to say Hoover doesn't value his earlier experiences. Yes, he says, he could have opened a business without working so long in the corporate retail world, but he gained confidence from doing well in that environment. "You've got to be smart and tough to make it in your own retail business today," he says -- and if smarts and toughness are what you get from a big-company career, then large-scale retailing provides a natural springboard into small.