(FORTUNE Magazine) – To select one man to be the Businessman of the Century is to look back upon almost unimaginable change. The world of Henry Ford (the earliest of the final four contending for the honor) and the world of Bill Gates (the latest) are as different from one another as Henry James from Toni Morrison, high tea from happy hour, or Queen Victoria from Bill Clinton. J. Pierpont Morgan was the most important businessman in America in 1900, but the circus of which Morgan was ringmaster was nothing like the one Alan Greenspan superintends today. No Federal Reserve, no income tax, no Securities and Exchange Commission, no institutional investors; no cars to speak of, few phones to speak through, no TV, no microwave dinners, no jet lag, no World Wide Web.

The world's economic center was London, capital of an empire larger and richer than any in history. In upstart America, only the upper-right-hand corner of the map counted for much. More people lived in Manhattan--1,850,000--than in all of California. More than half the value of all U.S. manufactures came out of New England and the Middle Atlantic states. Three out of five Americans lived on farms or in hamlets whose population was under 2,500; farmers produced more than a quarter of the private gross domestic product.

Yet the shape of the 20th century--the American Century--could already be seen. The years after the Civil War had been an age of entrepreneurs, who constructed and exploited transportation and communications networks that linked every place to every other. Carnegie, Fisk, Rockefeller, Vanderbilt--these men got unimaginably rich unbelievably quickly, at least by the standards of the time. Yet their era ended with the century. In 1896, John D. Rockefeller stopped going to the office every day, leaving Standard Oil to professional managers, and devoted himself chiefly to philanthropy. Five years later, in 1901, Andrew Carnegie folded his steel company into U.S. Steel and followed Rockefeller into a life of good works.

Organization Man rose to challenge the robber baron. The railroad and telegraph had created mass markets. New machines had made mass production possible. Business had to change to exploit these opportunities; big far-flung enterprises simply couldn't be financed or run by one tycoon, however rich or brilliant. He needed shareholders, hierarchies, business units, staffs. "Thus came into being," writes historian Alfred D. Chandler, "a new economic institution, the managerial business enterprise, and a new subspecies of economic man, the salaried manager."

The 20th century was the Century of the Manager--the century that invented management, even. In 1909, Frederick W. Taylor published his Principles of Scientific Management, the Summa Theologica of his faith that sound, fact-based management could improve productivity. In Vienna that year was born Peter F. Drucker, who turned management into a profession in such books as The Practice of Management and the monumental Management: Tasks, Responsibilities, Practices. Together Taylor, Drucker, and W. Edwards Deming, the founder of Total Quality Management, who was born in 1900, have had more influence on the conduct of business and the quality of life in the U.S. and abroad than any CEO. Deming's Fourteen Points, the basis of Japan's post-World War II miracle, improved the lot of more people than did Woodrow Wilson's Fourteen Points, his principles of peacemaking after World War I. As for Taylor, Drucker says, "Thanks to him, we have increased the productivity of manual work 3% to 4% compounded--which is 50-fold--and on that achievement rests all the prosperity of the modern world."

Yet it's impossible to conceive of America, even buttoned-down corporate America, without the restless entrepreneurial itch to go someplace new, do something new, become someone new. Management goes only so far; it stops a step short of genius. The peculiar gift of American capitalism seems to be its ability to keep both the manager and the entrepreneur in the ring, slugging it out forever, neither gaining a permanent advantage over the other. At midcentury, the beau ideal of business might have been the manager, but at the century's beginning--and certainly now at its conclusion--our heroes are builders, founders, risk takers.

These conflicting, complementary drives, this yin and yang, this compulsion to "make it new" vs. this "blessed rage for order," came up repeatedly as FORTUNE struggled to choose a Businessman of the Century. (Yes, alas, businessman: Our journalistic successors will choose the businessperson of the 21st century--and this time perhaps from a list not dominated by Americans.) Sam Walton or General Robert Wood? Bill McGowan or Theodore Vail? Over the past several months, FORTUNE has profiled the greatest business leaders of the 20th century. How to pick one to stand above the rest?

He should, clearly, be someone who was celebrated at the time he labored and is still renowned today--that is, a person who was conspicuously successful in both the short run and the long. He should have been captain of an enterprise of some scale. (No doubt there are men whose small businesses are unblemished gems, whose children and grandchildren sing their fame and enjoy their trust funds; but in this century, size matters.) And, we concluded, the Businessman of the Century should have been part of an industry that is characteristic of his time.

We narrowed the search to a final four. Each was the dominant businessman of a quarter of this century; each created or built a corporation that is still greatly influential today; each played a major role in automobiles or computers, the two industries that, more than any others, distinguish this century from those of the past. As it happens, the men are equally divided between entrepreneurs and managers: Two of them founded great concerns but also managed pretty well; two are masterful managers who also brought enormous growth and wealth to their employers. Now, the final quartet:

HENRY FORD (1863-1946) didn't invent the automobile, but he invented the automobile business. When he founded the Ford Motor Co. in 1903, cars were fussy, unreliable, costly novelties. Ford's genius was to make them simple, solid, and inexpensive necessities. In so doing, he built the largest industrial organization of the early 20th century and amassed a personal fortune of $1 billion ($36 billion in today's dollars), but he also placed himself at the forefront of a social revolution that had an immeasurable impact on American life. When he got his Model T rolling in 1908, the horse disappeared so fast that the conversion of acreage from hay to other crops is said to have caused an agricultural revolution. And that was only the beginning.

One of eight children, Ford was born in 1863 and attended a one-room schoolhouse before dropping out at age 16 to find work in the machine shops of nearby Detroit. He was working as the chief engineer at the main Detroit Edison electric plant in 1896 when he built a horseless carriage, the Quadricycle, in a shed in his backyard. Since it was too wide to fit through the front door of the shed, Ford had to knock out part of the wall to drive it out.

His device attracted investors, and after several false starts he founded Ford Motor. At a time when the automotive landscape was studded with Cadillacs, Packards, and Pierce-Arrows costing several thousand dollars or more, Ford wanted to build a car designed for "everyday wear and tear." He introduced the Model T at $850. It was homely but had the virtues of lightness, simplicity, and utility, and it became the most successful vehicle ever produced in America. More than 15.5 million were built during its 19-year run. Others would eventually target the mass automobile market--Chevrolet was born in 1911--but Ford came first.

To fill demand for the Model T, Ford had to scrap his manufacturing system, in which cars mounted on cradles were pushed from one workstation to the next while workers swarmed around them. In 1913, Ford redefined the work to stop the swarming--"The man who puts in a bolt does not put on the nut; the man who puts on the nut does not tighten it"--and roped the partially built cars together so they could be pulled past the workers at a predictable speed. In a single year, production doubled to nearly 200,000, while the number of workers actually fell from 14,336 to 12,880.

So demanding and numbing was the assembly-line work that Ford had to hire close to 1,000 workers just to keep 100. Thus he was persuaded to raise wages from the prevailing $2.30 per day to $5, though he insisted on calling the increase "profit sharing" to leave himself the option of withdrawing it in hard times. (Indeed, he did cut it to $4 in 1932.) The five-dollar day drew workers to Dearborn from all over the country. To make sure his employees didn't fritter their money away, Ford created the Sociological Department, whose members visited workers in their homes, handing out pamphlets that urged them to use plenty of soap and water and not to spit on the floor.

Before the Model T, manufacturing was done by craftsmen who made things one at a time. But as Ford adapted the emerging principles of mass production to the automobile and hired tens of thousands of workers to put those principles into practice, he gave rise to an entirely new phenomenon: the blue-collar middle class. Because the jobs were simple and repetitive, he could employ farmers, immigrants, and others who previously had done only manual labor. The five-dollar day gave them the income they needed to afford a home and support a family--and to buy the cars they were making. In creating a huge body of people who shared not only their work but many social and economic interests, Ford, to his lasting regret, spurred the development of industrial labor unions.

But the unions came much later. As Ford became more successful, he was increasingly portrayed as a folk hero who hung on to his rural values in an increasingly industrialized world. He spouted homespun aphorisms ("Failure is only the opportunity to begin again more intelligently"). He gave old-fashioned dances at which he introduced his wealthy guests to the Virginia reel and the quadrille. He launched the Peace Ship in 1915, went on camping trips with Thomas Edison and Henry Firestone, and built an idealized rural enclave that he named Greenfield Village.

Meanwhile, Ford paid less attention to managing the enterprise he had created. He spent little time in his office, preferring to roam the factory floor. Balance sheets and operating statements meant nothing to him. He distrusted bankers and kept large sums in cash so he wouldn't have to borrow money. He disdained organization charts and job descriptions and delighted in pitting executives against one another. A manager arrived at work one day to discover that his office had been moved into the men's bathroom, with only a flimsy partition between his desk and the toilet. He quit the same day.

If Ford had had his way, he would have built the Model T forever. When he finally changed models in 1927, he laid off his workers and shut down production for six months while he engineered its replacement. It was too late: General Motors took the lead in car sales in 1931 and has never relinquished it. Increasingly whimsical and capricious, Ford reigned over a failing company run by sycophants and thugs until his wife and daughter-in-law forced him to turn it over to his grandson Henry II in 1945.

They were just in time. Ford Motor prospered with more professional management and now ranks as the world's second-largest industrial company (after General Motors), with revenues of $143 billion. And the company has stayed in the family for four generations. Old Henry's descendants own 6% of Ford Motor stock, and his great-grandson William Clay Ford Jr. is chairman of the board. As for his larger legacy, well, just look around you.

ALFRED P. SLOAN JR. (1876-1966) sold roller bearings to Henry Ford in the early years of the century. Not much later, Sloan brought Ford Motor nearly to its knees.

Sloan's father had bought Hyatt Roller Bearing for his son in 1898 for $5,000. In 1916, Alfred Jr. sold it for $13.5 million (2,700 times the initial investment) to William C. Durant. Two years later Durant folded Hyatt into General Motors, and Sloan became a vice president and a member of GM's executive committee.

GM was such a hodgepodge of uncoordinated enterprises, and Durant such a slipshod manager, that Sloan nearly quit in frustration. He didn't have to. In 1920, GM's debts and inventories collided with a collapse in automobile sales, and the company nearly failed. Durant was forced out, and in 1923, Sloan became president. He remained chief executive officer until 1946.

During those 23 years, Sloan invented the art of managing a large corporation. First he created a corporate office, whose job was to allocate resources and coordinate the company's operating divisions but not to run them. From corporate, every division got whatever it needed--money, factories, sales forces--to operate autonomously. To link the divisions, Sloan promulgated a set of "standard procedures" for budgeting, hiring, forecasting, reporting sales, etc., and also created interdivisional councils where executives and staff could share ideas or find ways to exploit economies of scale. Sloan got it just right: His GM had the right amount of central control, the right amount of divisional independence, and plenty of ways to share ideas. If Sloan's management record has one blemish, it was his stubborn refusal to meet with representatives of the new United Automobile Workers Union--an intransigence that led to a series of sit-down strikes in 1937 and, ultimately, to the company's agreeing, under heavy government pressure, to recognize the union. But if Sloan found organized labor difficult to deal with, he was hardly alone.

Sloan was as brilliant at strategy as he was at organizing. From 1908 to 1927, Ford produced just one car--the Model T. Sloan, on the other hand, had inherited an ill-sorted collection of models from Durant; in a classic bit of managerial jujitsu, he succeeded in turning that liability to his own advantage. Vowing to produce a car "for every purse and purpose"--from the aristocratic Cadillac to the proletarian Chevrolet--he modified his lines accordingly. As a result, Ford's share of U.S. motor-vehicle sales fell from 55.7% to 18.9% between 1921 and 1940, while GM's rose from 12.7% to 47.5%.

Sloan told his own story in My Years at General Motors, but his tale is not just written there. It is written also in the annual reports and organization charts of nearly every large business in the world. It was at Sloan's General Motors that Peter Drucker learned the gospel of management he has spread through his own consulting and writing. The modern divisionalized corporation was in large part Sloan's creation. He showed how to set it up and make it work. Every leader since stands on his shoulders--up to and including FORTUNE's Manager of the Century, Jack Welch, the current master of the art Sloan invented. (For more on Welch, see "The Ultimate Manager.")

THOMAS J. WATSON JR. (1914-1993) had his father to thank for his start at IBM, but to earn his place in the business pantheon, he had to fight the old man out of the way. Watson Sr. was one of the great entrepreneurs of the first half of the century. A sales genius, he persuaded businessmen to lay down their ledgers and trust their bookkeeping to primitive accounting machines that used punch cards. He put IBM on the map. He gave the world the motto THINK.

But it was Watson Jr., his first-born son, who pushed IBM into computers. After taking over from his father as CEO in 1956, he led the company through one of the longest and most spectacular bursts of growth ever seen. The IBM he shaped was the greatest success story of America's postwar boom--the company that sprang to mind whenever talk turned to the American corporation and the Organization Man. By the time Watson Jr. left IBM in 1971, it had routed computer-industry rivals like General Electric, RCA, and Sperry-Univac; in size and importance, it had elbowed its way past the smokestack giants that had dominated American business. During his tenure, IBM created more wealth for its shareholders than any company in business history--an achievement that stood until the bull market of the 1990s and that led FORTUNE in 1987 to declare Watson "arguably the greatest capitalist who ever lived."

Growing up in the shadow of his hot-tempered father, Watson Jr. was a slow starter who showed no inclination for business. He barely made it through Brown University and spent a few unhappy years in the late 1930s selling his father's punch-card machines by day and frequenting Manhattan nightclubs after work. Then came World War II, from which he returned a seasoned Air Force pilot and a changed man. Having flown B-24s and DC-3s on dangerous supply routes across Russia, India, and China, Watson was ready to prove himself his father's equal. The struggle to transform IBM from a midsized growth company into a multibillion-dollar money machine became a battle between the Watson generations as well.

For ten tempestuous years, father and son worked together, the elder Watson teaching Tom his business secrets and, at the same time, second-guessing his son and challenging him in operatic clashes. Computers were one of their many flash points: Watson Sr. did not see much potential in the U.S. government's primitive ENIAC, a room-sized, pea-brained number cruncher that ran on unreliable vacuum tubes. In his view, a computer revolution might sweep across the scientific world, but in the accounting room the punch card was going to stay on top.

Young Tom saw things differently. He sensed the vast opportunity in electronics and also a dire threat to IBM itself when big organizations began ordering Univac computers. Developing IBM's first computers meant doubling the R&D budget and hiring hundreds of electronics engineers--steps it took years to persuade the old man to take. But by the time Watson Sr. handed over control in 1956--six weeks before his death--the computers his son had championed were the hottest product in American business.

Watson Jr. was an intuitive leader, driven by the urgency of keeping pace with the computer revolution. His IBM at its peak hired and assimilated tens of thousands of employees per year; Watson virtually wrote the book on managing fast, sustained, hugely profitable growth. The key, he understood, was speed: "The worst possible thing we could do [was] to lie dead in the water with any problem. Solve it, solve it quickly, solve it right or wrong. If you solved it wrong, it would come back and slap you in the face, and then you could solve it right."

A tough boss, he helped set the high-stress tone of executive life in the 1950s and '60s. While his father had been a magnet for yes men, Watson Jr. surrounded himself with what he called scratchy individuals: "I never hesitated to promote someone I didn't like. The comfortable assistant--the nice guy you like to go fishing with--is a great pitfall. I looked for those sharp, scratchy, harsh, almost unpleasant guys who see and tell you about things as they really are." For those who erred, he devised the so-called penalty box--a temporary but humbling transfer off the fast track. Sometimes the penalty wasn't so temporary. Watson put his younger brother Dick in charge of IBM's bet-the-company gamble to develop System/360, a line of computers intended to render its previous machines obsolete. When the project fell behind schedule, Watson demoted Dick, effectively ending his IBM career.

For all its rigors, Watson's IBM was synonymous with opportunity. It became famous for putting all its workers on salary, for its generous compensation and benefit plans, and for virtually guaranteeing lifetime employment. Unprecedented growth paid for the beneficence. Long before there were Microsoft millionaires, IBM millionaires peppered the regions where the company had installations--longtime employees who had bought company stock and owners of the stock options that Watson Jr. distributed liberally to executives. Despite the wealth Watson created, however, the family fortune never approached those of today's high-tech tycoons. His father never owned more than 5% of the company; as early as 1957, Watson Jr. and Al Williams, his top lieutenant, stopped taking stock options. (Said Watson: "We didn't want to look like pigs.")

Watson's commitment to IBM was not a lifelong vow. He had passions he could turn to outside business, and after suffering a heart attack at age 57, he stepped down. For the next two decades he mixed public service with a life of adventure suited to a man half his age. He was Jimmy Carter's ambassador to Russia, on station in Moscow during the invasion of Afghanistan and Carter's reprisals. He chaired a U.S. arms-control commission and toured America stumping for nuclear disarmament. For fun, Watson flew jets, helicopters, and a stunt biplane. He took small sailboats on grueling voyages to the Antarctic and Hudson Bay, expeditions that won him yachting's equivalent of the Nobel Prize, the Blue Water Medal. Watson not only knew how to run a business--he had a life.

WILLIAM H. GATES III (1955-), a.k.a. the World's Richest Man, is usually portrayed as the consummate computer geek. Editorial cartoonists and magazine illustrators love to caricature his dweeby spectacles, intransigent hair, and quaintly ill-fitting clothes. Business journalists relish describing his idiosyncratic physical mannerisms and his goofy, jargon-laced speech. Indeed, Gates himself seems to cultivate a nerdy image.

But the reality is that Gates is, if anything, the quintessential fin de siecle businessman--a hypercompetitor who combines equal parts technologist, entrepreneur, and corporate architect. Though it's been decades since he actually wrote computer code, he still peruses the work of key programmers and makes detailed suggestions for specific products. Perhaps the shrewdest business strategist of the last quarter of the century, Gates has flummoxed much larger competitors like IBM and found ways to steal the march on brilliant IT innovators like Apple and Netscape. And unlike most techno-entrepreneurs of his generation, Gates' skills as an imaginative manager and leader have kept pace with his company's breakneck growth.

But the amazing thing about the 44-year-old Gates is that he's been more or less like this since he was 13. That's when, as a raw eighth-grader, he started his first company. Traf-O-Data harnessed a computer-like device to track and analyze traffic at busy Seattle intersections. To this day, Gates rues the fact that Traf-O-Data never made a profit--even back then he expected to make money. Indeed, Gates was the kind of kid who would abscond with his dad's copy of FORTUNE and read it in bed late at night with a flashlight.

By now the Bill Gates bio is pretty well-known. He is the scion of a wealthy and prominent Seattle family. A brilliant but under-achieving student, he attended Seattle's exclusive Lakeside School, where he met his first computer, as well as Paul Allen, the burly buddy with whom he would later found Microsoft. Gates attended Harvard for a couple of unsatisfying years, and toward the end an unemployed Allen joined him in Cambridge. It was Allen who came across the fateful January 1975 issue of Popular Electronics that featured on its cover a photo of the very first personal computer, the MITS Altair. The accompanying article prompted Gates to drop out and move with Allen to Albuquerque to start Microsoft. The rest, as they say, is history.

Now, of course, Gates is the CEO of the most valuable company in the world. Gates, like Henry Ford, brought what was previously a technological curiosity to the masses. Microsoft Windows and its predecessor, the MS-DOS PC operating system, were the high-tech equivalents of Ford's Model T. They may not have been the sleekest or most elegant pieces of software, but Gates figured out how to make them almost universally used, and they transformed the entire IT world.

But if you stop and really think about it, Microsoft the company is probably more of a marvel of human creativity and ingenuity than any of its products. Before Gates and Allen started Microsoft, pure software companies didn't exist. Gates identified a business opportunity in what most computer companies saw as a necessary but nettlesome accoutrement to the hardware that pulled in the big bucks. In the end he created a masterpiece.

There's another, equally important way in which Microsoft is a new kind of company: It was one of the first to use stock options as an integral element of compensation for all employees, not just top executives. As a result, Microsoft has minted literally thousands of millionaires, not to mention a handful of billionaires, and has cemented employee loyalty in an era and industry rife with job hoppers.

As the century began to wind down, Gates' reputation as a boy wonder eroded somewhat, and not merely because his face began to reveal the crow's-feet of middle age. The ongoing antitrust trial--which will likely conclude soon--not only revealed a ruthless side to both Gates and Microsoft, tarnishing the reputations of both, but also seemed to signal that the company had reached its apogee in the industry. Gates may have stifled Netscape, but the decentralizing revolution continues in spite of him.

In the end, what most people think of when they think of Bill Gates is money. His Microsoft stock has multiplied in value nearly 100 times in the past decade alone; his breathtaking accumulation of wealth--$104 billion or so at last count--is the largest ever, even adjusted for inflation. If anything, he has devalued the significance of being a mere billionaire.

The truth, though, is that Gates is far from obsessed with money. He has said he intends to give his fortune away, and he's already off to a pretty good start: The Bill and Melinda Gates Foundation, with an endowment of more than $17 billion, is now the wealthiest in the United States. That remarkable philanthropy is only possible, of course, because of the astonishing fortune Microsoft and Gates have created. Gates the Geek, Gates the Giant Slayer, Gates the Gazillionaire--they are all one person, and he is one of the most remarkable figures of the century.

The four companies headed by Ford, Sloan, Watson, and Gates remain fierce competitors in their respective industries. Of the four, GM struggles most, seemingly unable to find a vision and strategy that will revitalize its business. Ford, already more profitable than GM, is poised to overtake it as the world's biggest automaker--something that hasn't been true since Henry Ford and Alfred Sloan were duking it out in the 1920s and 1930s. IBM is resurgent under Lou Gerstner, a CEO of the managerial school, while Gates and Microsoft, the most valuable company anywhere, continue to operate in entrepreneurial mode as they try to make the company as dominant in cyberspace as it has been on the desktop.

How can one pick among these four men, each an extraordinary leader, each astoundingly successful, each the progenitor of a legacy that has--or will have--long outlived him? Certainly they have all changed our world. The very landscape of America--and increasingly of the planet--has been transformed by the automobile. For good or ill (for good and ill), we live in suburbs, shop in malls, drive our Ford pickups and Chevys to work and school. Everything we do at home, while shopping, at work, or at school is inextricably bound up with the computer--whether it's the giant IBM mainframe that processes our credit-card charges or the Windows-equipped PC on which our children chat online.

Of the four men, Watson--businessman, pilot, sailor, diplomat--had the most soul and probably the most fun. It's not Watson's fault that IBM was clobbered by Microsoft after his time. But for all Watson's importance in business, his legacy seems most confined to business.

If size mattered most, then Sloan or Watson might win the nod--Microsoft's no pip-squeak, but it's only No. 109 on the FORTUNE 500, and it was Sloan who showed the world how to build a giant corporation and make it work. Sloan has the added merit of having competed directly with one of his fellow finalists--leaving Henry Ford sucking GM's exhaust. Indeed, the only one of these men who's alive to vote for the Businessman of the Century--Gates--says Sloan would be his choice; Gates once hung a photograph of Henry Ford in his office, he said, as a reminder of how the mighty can fall.

But oh, how they can inspire us as well--and business, like life, is about inspiration as well as perspiration, about vision as well as achievement. It is the entrepreneurs who inspire us, and it is from our two entrepreneurs that FORTUNE has chosen the Businessman of the Century. Curiously, their visions are much alike, if you adjust for the less florid language of our time. Thus Henry Ford: "I will build a motor car for the great multitude...constructed of the best materials, by the best men to be hired, after the simplest designs that modern engineering can devise...so low in price that no man making a good salary will be unable to own one and enjoy with his family the blessing of hours of pleasure in God's great open spaces." And Gates: "A computer on every desktop and in every home," and "Where do you want to go today?" Both are very American sentiments, democratic in their promise of opportunity, optimistic in their view that life is a journey to an ever new frontier.

Gates' story is far from over, of course--a lot could happen to burnish or blot his memory. Ford's is stained already. In his latter years he surrounded himself with goons, spouted ugly anti-Semitic bile, and left his company in terrible shape. He was, without question, the worst manager of this quartet--yet he was also the greatest managerial thinker. No fewer than three of the biggest management brainstorms of the century happened in Ford's head: the idea of a moving assembly line, the idea of paying workers not as little as possible but as much as was fair, and the idea of vertical integration that made Ford's River Rouge plant the chief wonder of the industrial world. The oil industry, the highway-construction industry, nearly universal homeownership--all these things, from Big Oil to Big Macs, can trace their parentage to the Model T Ford. The American Dream itself is inextricably linked to the automobile.

The Businessman of the Century was the builder of an industry that transformed the very land we live on, the first to create a mass market as well as the means to satisfy it, as great an entrepreneur as we've ever seen. He was a provincial and a curmudgeon; a man with all the prejudices of his time, who had as well the kind of genius that endures. He is Henry Ford.