The biggest mystery of the new millennium started with an errant e-mail.
In the beginning, it was just a book proposal — a series of cyberspace communiques in which an author told an agent that he had the scoop of a lifetime: One of today's most respected inventors was working on a device that would shake civilization.
It "will sweep over the world and change lives, cities and ways of thinking," the proposal read, according to a story on the site Inside.com.
What was it? He didn't say, only dropping a few hints and a name: "Ginger."
Months later, Ginger is still just that — a phenomenon. Since Inside.com published passages of the e-mail in January, Web prophets and curious journalists have posited that the device might be anything from a transporter to a hovercraft.
Yet the answer remains a mystery. And the unusual amount of speculation the invention has fueled is sparking the usual backlash — including from the inventor himself, a reclusive individual who has had some success turning quixotic ideas into reality. In an interview last week with Brill's Content magazine, Dean Kamen, the man behind Ginger, dismissed much of the coverage as "hype about a product that doesn't even exist yet."
But the hype remains. Websites like theginger.com and theitquestion.com have sprung up simply to disseminate the latest rumors. The prevailing theory at the moment is that Mr. Kamen is working on an idea that could reshape how people heat their homes or get to the market.
In a new story published last week, Inside fueled speculation that Ginger is a motorized scooter equipped with a unique balancing mechanism of gyroscopes and sensors called "dynamic stabilization." After all, Ginger's other code name, "IT," has been rumored to mean "Individual Transport." Also, in 1999, Kamen created a company intended to make "motorized . . . scooters, carts and chariots," Inside says.
Further on, however, Inside indicates the scooter might not be the true invention. Kamen has registered Internet domain names including "stirlingelectric.com" and "stirlingscooter.com," leading to speculation that he is refining a version of the Stirling engine.
Invented by the Rev. Robert Stirling of Scotland in 1816, the Stirling engine has long been a curio and niche product. Some remote Arctic outposts use it for power, and Swedish submarine-maker Kockums builds its craft with Stirling engines.
The allure is obvious. The engines — which work by using heated and cooled gas, not internal combustion, to move pistons — are quiet and environmentally clean.
Scientists tried to adapt Stirling engines for cars during the 1970s but never succeeded. The contraptions remain slow to start and relatively costly. But if Kamen can improve on the engine, the impact could be profound.
The scooter is fine, say experts, but perhaps the most alluring Stirling application would be as a household power source. Forget the inefficient process of importing power from a far-off plant — an advanced Stirling engine no bigger than an air conditioner could sit in the back yard and meet a household's electricity needs.
"The significance of the Stirling engine is that you could obsolete the electric grid," says Brent Van Arsdell, president of American Stirling, which builds engines mainly for educational uses. In addition, "a whole range of Stirling engines could be developed to even run things like a laptop."
Mr. Van Arsdell says he knows of several companies that are working on improved Stirling engines, but Kamen's reputation for turning ideas into reality is almost mythic. As of last month, he held 96 patents in the United States, and his most recent invention won him the National Medal of Technology last year. It was a wheelchair code-named "Fred" (hence: "Ginger") that can go upstairs, over sand and raise its owner to eye level with standing people.
In his personal life, Kamen fits the image of the eccentric inventor. Every day, he wears the same outfit: blue jeans and a denim shirt. He commutes the seven miles from his suburban home to his Manchester, N.H., R&D company by helicopter. What's more, he's the pilot.
He's even bought his own island, North Dumpling, in Long Island Sound. When New York officials wouldn't let him build a windmill there to power his home, he declared that North Dumpling had seceded from the Union and proclaimed himself "Lord Dumpling." The island has its own currency and a navy — an amphibious vehicle dubbed "Old Aluminumsides."
"He's someone who enjoys being an iconoclast," says John Abele, founder and chairman of Boston Scientific, who has known Kamen for about 10 years.
The son of a comic-book artist and a teacher, Kamen has done well for himself. He dropped out of college at Worcester Polytechnic Institute in Massachusetts and invented a portable drug-infusion pump. By 1996, that invention — as well as the invention of a compact kidney-dialysis machine — had brought Kamen $30 million, according to Forbes magazine.
Kamen is known to be a friend of President Bush, and each presidential candidate visited Kamen's home during last season's campaign. In many ways, the $3.1 million house is an attraction in itself. It's hexagon-shaped and has an indoor pool, a softball field, a pulley that can ferry bottles from the kitchen to the bedroom, and a helicopter hangar.
Aside from his fascination with innovation and aviation — he also owns a jet — Kamen is an ardent booster for the cause of science. He has created FIRST (For Inspiration and Recognition of Science and Technology) to encourage kids' interest in science, and he founded a children's science museum in Manchester.
Repeatedly, he has lamented that athletes are revered and scientists are anonymous. It is the buzz about Ginger, however, that seems to be inadvertently raising his profile and that of science worldwide.
"This came at a time when all the stories in the technology sector were bad news," says Paul Saffo of the Institute for the Future in Menlo Park, Calif. "It also was a mystery, and it involved the notion of the solo inventor. . . . When the stars line up in a certain way, then something like this takes off."