AS RECENTLY AS 1970 THE ONLY WAY doctors could see inside a patient’s body without surgery was with X rays. This technology, which dated back to the horse-and-buggy era and had seen few improvements since, amounted to a form of two-dimensional photography, complete with negatives and film. During the 1970s and 1980s, however, three separate new methods combined to greatly expand a physician’s ability to find and diagnose potentially dangerous conditions.

AS SOON AS THEY LEARN TO RECOGNIZE numerals, most children notice an enigma that presents itself every time they visit a store: Why do so many prices end in 99? Some children shrug it off as one of the unaccountable mysteries associated with grownups, like cauliflower or social studies. Others ask an adult and are told that $5.99 is supposed to look cheaper than $6.00, even though the ruse is apparent to a small child. In fact, every shopper mentally rounds off such prices to an even dollar amount.

LAST SUMMER MY EMPLOYERS ASKED ME, AND quite a few other people at the company that owns this magazine, to attend a one-day management-training seminar given by a management consultant in a conference center high above Wall Street.

SAY YOU WANTED TO BRING UP TO DATE CHRISTIAN SCHUSSELE’S 1862 MASTERPIECE Men of Progress , a heroic four-by-six-foot scene of nineteen innovators of the age. Whom would you put in it? Who are the men of progress, or the men and women of progress, or whatever you would call them now, of the twentieth century?

At the risk of reigniting the “redgreen” wars brought on by the merger of the Pennsylvania and New York Central Railroads in 1968, I feel compelled to offer comment on “Postfix: Jet Train,” by Ed Pershey, in your Fall 1999 issue. I was at the time the Pennsylvania Railroad’s coordinator of the Northeast Corridor Demonstration Project, a government-railroadsupplier partnership that ultimately brought the Metroliner and Turbotrain to service in 1969.

THE NATURAL PROCESS OF REFLECTING ON THE PASSING century involves much pride in technological achievement. It is, after all, the century of wireless communications, jet travel, space exploration, and computer networks.

At first it looked almost too easy. Emilio Emini had all the sophisticated tools of modern science to deploy against the virus. Tall, articulate, and energetic, trained in microbiology at Cornell University and able to muster the resources of one of the world’s leading research companies, he was in the prime of his scientific career in 1986 and was eager to meet the challenge. His opponent, identified only three years before, was a virus that needed to be in an animal to live, and even then half its population would die within a day.

Itzhak Perlman has called Jascha Heifetz the “father of modern violin playing,” and Isaac Stern credits him with extending the range of the possible more than any violinist before or after. When in 1972, in Los Angeles, Heifetz gave his last public concert, the standing-room-only crowd included luminaries from throughout the violin world as well as a young Hollywood studio musician and Heifetz student named Ron Folsom.

A Dangerous Stunt?

At the risk of reigniting the “redgreen” wars brought on by the merger of the Pennsylvania and New York Central Railroads in 1968, I feel compelled to offer comment on “Postfix: Jet Train,” by Ed Pershey, in your Fall 1999 issue. I was at the time the Pennsylvania Railroad’s coordinator of the Northeast Corridor Demonstration Project, a government-railroadsupplier partnership that ultimately brought the Metroliner and Turbotrain to service in 1969.

IT IS A CURIOUS PARADOX OF AMERICAN LIFE THAT IN many municipalities bar patrons are not allowed to smoke, yet they can spend all night polluting the atmosphere with out-of-tune caterwauling to a karaoke machine and remain sadly beyond the reach of the law. Even the staunchest advocates of free trade might abandon their principles when faced with the threat from this particular Japanese import.

You had to be rich to own a car radio in the late 1920s and early 1930s. Installed, a decent set might cost you $175. Since you could by a new 1930 Chevrolet sedan for $695, a radio represented a pretty hefty piece of change.

The name suggested mild titillation; the plate on the device promised “tingling relaxation and ease.” Twenty-five cents, and it would shake the mattress under you for 15 minutes, probably 14 minutes more than anybody could ever really want. The genius behind this 1958 invention was a former salesman named John Houghtaling.

ON JULY 10, 1962, IN WASHINGTON, D.C., VICE President Lyndon B. Johnson picked up the telephone to chat with Frederick Kappel, the chairman of American Telephone and Telegraph (AT&T). Kappel was calling from Andover, Maine. For about two minutes the men traded platitudes about the potential benefits of satellite communications and the need for government and industry to work together. Then they thanked each other and hung up.

It was as plain as daylight to any rationally thinking oilman in the early part of the century that vast oceans of oil must lie under the world’s seabeds. After all, the same geological pressure cooker that had turned ancient organic matter into petroleum under the Texas cap rock had to have worked just as well under the ocean, hadn’t it? The oil was there all right, but it was tantalizingly out of reach. A smart geologist could almost see it. It was like looking at snowcapped peaks from the floor of a desert—all that lovely water so close, and no way to get at it.

SNEAKERS WERE NOT POSSIBLE UNTIL CHARLES Goodyear made rubber useful. Rubber, derived from latex, the milky sap of the South American hevea tree, had interesting properties. It was both waterproof and elastic, and rubber-soled shoes could absorb the countless shocks that feet suffer in running and jumping—something that couldn’t be said of leather boots, which remained the footwear of choice for both work and play through the late nineteenth century. But rubber also melted in warm weather and became cracked and brittle in the cold.

MOST MAJOR WARS OF THE TWENTIETH CENTURY have contained deadly previews of the next conflict on the timeline. Aviation technology and aerial warfare provide excellent examples of this pattern. In World War I the airplane was hardly decisive, yet the opposing powers discovered its usefulness in reconnaissance, bombardment, and air-to-air combat, a lesson applied during the 1930s in the Spanish Civil War, which today is seen by many as a rehearsal studio for the German and Soviet fighter and bomber tactics of World War II.

HOW DO YOU GET A PERSON TO FEED MONEY INTO A DEVICE that serves no function but to give only some of it back? Slot-machine designers have always had an intuitive grasp of the arts of both P. T. Barnum and B. F. Skinner, mixing two parts sucker appeal with one part operant conditioning. Their devices have been caressed and kicked, prayed to, execrated, and suspected of malign intelligence. They have soaked up billions in profits and attracted a century of legal suppression.

A CENTURY AGO, WHEN THE AGE OF THE AUTOMOBILE WAS JUST BEGIN ning, few people worried about what would happen when cars began to wear out. After all, there were plenty of junkyards, where horse carts and carriages and all the other conveyances of premotorized America ended their days. If anyone did think about it, they probably figured that old automobiles would be taken apart and sold for scrap, just like their predecessors.

THE SPRING 2000 ARTICLE ABOUT calculators (“How the Computer Got Into Your Pocket,” by Mike May) shook loose a memory for me. In 1974 my high school precalculus teacher recommended that we buy slide rules to aid our calculations. Almost all of us ordered and awaited delivery of the mysterious devices. The big day arrived and I expected we’d spend the hour learning the rudiments of our enigmatic new tools.

Today’s high-tech innovators know that simply creating a clever bit of technology is no guarantee that it will be adopted. In many cases an invention does not become accepted until it is used in a “killer application”—something irresistible enough to overcome people’s natural reluctance to change. Thirty-five years ago Texas Instruments (TI), with headquarters in Dallas, faced the same problem.