(FORTUNE Magazine) – Lest you think the Internet spawned this consumer-friendly age of direct, hassle-free retailing, consider the legendary General Robert Wood. Director of construction for the Panama Canal, he was the U.S. Army's chief supply officer during World War I. A born strategist (and oddball hobbyist--his favorite reading was Statistical Abstract of the United States), Wood studied population flows and foresaw the postwar economic boom in and around America's big cities. When he went to work for catalog merchant Montgomery Ward in 1919, he pestered his bosses about how selling direct--in those days, by mail order--was an outmoded way of doing business. To be modern, Wood contended, Ward needed to physically set up shop where the consumer was: on the expanding network of highways, with big, easy-to-shop stores. Ward's CEO rejected the notion and fired Wood. But Sears Roebuck hired the pesky general, embraced his strategy, and took the leap from direct mail into bricks and mortar. Before long Sears was an icon of innovation and the largest retailer in the world.

If anything unites this century's giants of retailing--Sam Walton of Wal-Mart, Home Depot founders Bernie Marcus and Arthur Blank, Amazon.com's Jeff Bezos, and Wood, who was elected chairman of Sears in 1939 and led the company through 15 years of tremendous growth--it's that they understood where the consumer was headed, both geographically and psychographically. They bet their reputations, they scraped and floundered, they faced doubt and even dismissal. But in the end, of course, all that just fueled their drive to win.

No one defied the conventional wisdom more consistently than Sam Walton. While Sears and other renowned merchants plunked their big stores in the cities and the suburbs, Walton saw his opportunity in rural America. In retrospect, the insight seems inevitable: Major retailers hadn't yet located there. But the man who would eventually build the world's fourth-largest corporation ($139.2 billion in 1998 revenues, behind General Motors, DaimlerChrysler, and Ford) was neither an obvious nor an overnight success. Walton was a 44-year-old variety-store operator in 1962 when he opened his first Wal-Mart in Rogers, Ark. And he didn't even invent discounting (buying direct from manufacturers and displaying the stuff in bulk): Kmart, F.W. Woolworth's Woolco, and Dayton Hudson's Target all started that same year.

So what made Walton the merchant king? He chose his sites more skillfully, by buzzing his airplane low over the crossroads between small towns. He also delivered his merchandise more smoothly, by investing heavily in high-tech logistics systems. Like a stealth flier eluding enemy radar, Walton went unnoticed by his rivals until well into the '80s; in fact, Sears' neglect of Wal-Mart was a major reason for its decline. Yet the revolution that "Mr. Sam" began was no less than the democratization of the economy. Following an era in which suppliers told retailers what to buy and merchants spoon-fed consumers, Walton squeezed suppliers' profit margins and funneled the savings to the public. ("We sell for less, always," he said in his ads.) Consumers made out, as did the visionary in the red pickup truck: When Walton died in 1992, he was America's wealthiest man. And he paved the way for a new breed of retailer--the category killer.

Following Wal-Mart's success, a slew of high-volume niche operators--Toys "R" Us, Circuit City, Barnes & Noble, Blockbuster--blew into America's suburbs, putting less efficient merchants out of business. But it was Home Depot, the uber-killer with the lethal mix of low prices and topnotch service, that really buzz-cut the competition. As it happened, Bernie Marcus, a former pharmacist, and Arthur Blank, an accountant, were fired from their first big jobs in retailing. Soon after, when they found a wealthy financier to back their own chain of big-box hardware stores, the voluble Marcus got into such a squabble with the investor that he and Blank decided to pass on the guy's money. Too bad for Ross Perot: The $2 million stake he almost invested in Home Depot in 1978 would be worth $60 billion today.

Only a few years ago, a new figure wandered into this land of unlikely retail giants: A scrawny, 30-year-old former hedge fund manager who drove west in his Chevy Blazer (shades of Mr. Sam's pickup) to open a store where the consumer was moving--online. He's a hardscrabble entrepreneur (he built his desk himself, with four-by-fours from Home Depot) and a shrewd CEO who recruited information-systems pros from none other than Wal-Mart. In fact, Jeff Bezos' bodysnatching got Amazon sued by Wal-Mart for stealing trade secrets. (The parties settled.) "If Sam were still alive, I don't think Wal-Mart would have sued us," says Bezos, who is deceptively boyish and charmingly earnest. "Sam would've said to his people, 'How'd you let 'em go?!'"

Bezos has weathered the usual derision. Since Amazon opened its "doors" in 1995, "we've been called Amazon.con, Amazon. bomb, and, my favorite, Amazon.org--which is clearly because we're a not-for-profit company," he says. But in building the leading e-retailer, with revenues of $610 million last year and a current stock-market value of $22 billion, Bezos has more than survived. Beginning with books, then CDs and videos, he has lately branched out into toys, consumer electronics, and online auctions. Now he's determining what Amazon will ultimately be. The Wal-Mart of the Web? Not quite: "We want to build the most customer-centric company in the world." You don't make it to these pages by being shy.

This is the eighth in a series of features nominating finalists for our BUSINESSMAN OF THE CENTURY award. We will announce the winner in the Nov. 22 issue of FORTUNE. Stay tuned.