Masters of Invention We rounded up the world's most prolific inventors alive-three of them have more patents than Thomas Edison-and asked them the big question: Where do the big ideas come from?

Shunpei Yamazaki is the most prolific inventor in history, but you've probably never heard of him. He is 65, runs a research and development company-Semiconductor Energy Laboratory, in Atsugi, Japan-and holds 1,811 U.S. patents, nearly 700 more than Thomas Edison. This neatly dressed, polite, trumpet-voiced man, who comes across as something of a mystical seeker, attributes his success to six years under a mentor who taught him the "emotional spirit" of inventing. For Yamazaki and his peers, inventing is much more than just making money from intellectual properties; it's anything from a compulsion to a calling. Invention is the engine of industry and the raison d'�tre of nearly every technology company. More than that, it advances civilization. Yet our greatest creators don't have rock-star status. Oh, there's Edison, the Elvis of inventors, and a thin sliver of society knows about contemporary pioneers like Dean Kamen, who created the Segway, and Tim Berners-Lee, who is credited with envisioning the World Wide Web. But the most successful living exemplars have a Q rating somewhere below that of an extra in Gigli.

Inventors are undervalued but not without controversy. Nearly 90,000 U.S. patents were granted in 2006, up 50 percent from a decade ago-an explosion that has created a mess for some companies. Rampant legal fights over who devised what have become yet another cost of doing business, especially in the technology sector. Overwhelmed examiners sometimes grant questionable patents, and the U.S. Patent and Trademark Office is so inundated that years can go by between submission and approval.

Despite the systemic muddle, anyone who ranks in Edison's class has lived a remarkable life. I wanted to interview the top 10 living patent holders worldwide-ranked here in order of their number of U.S. patents-in the hope of gaining some insight into the creative spark behind invention. But first I had to find out who they are. Astoundingly, the patent office does not keep such a list. No one does. At the request of Cond� Nast Portfolio, the Patent Board, a Chicago patent research and advisory firm, ran the query and came back with the names. (Granted, a tally of the number of patents does not necessarily identify the "greatest" inventors, just as book sales rarely reveal the finest writers. But such a list is the only objective measure we have.) These men-the group is all male-have rarely, if ever, talked to the media. During four months of phone calls and cajoling, I persuaded nine of the top inventors to agree-often reluctantly-to interviews

Identifying them turned out to be easier than tracking them down. Two of the men do not work in the United States. Four are with a relatively small company, Micron Technologies of Boise, Idaho. Six, including Yamazaki and the four from Micron, work on computer chips. Missing from the list is George Spector, No. 4, who is apparently not an inventor at all. For decades, he ran a New York business that helped small-time inventors obtain patents for novelty innovations such as a motorized pot-washing tool. Spector then added his name to those patents, ultimately netting him 722.

None of the top 10 created any game-changing devices on a par with Edison's lightbulb, but most people benefit every day from some discovery by the creative minds in the chip business whose efforts have improved laptop computers, cell phones, and digital cameras. Kia Silverbrook, the most secretive, runs Silverbrook Research in Sydney, where he has led a decadelong, superstealth effort to create new computer-printer technology that could be on the market by 2009. At the opposite end of the technology spectrum, Donald Weder holds 1,350 patents, all from his work at Highland Supply Corp. in Highland, Illinois-a decorative-packaging company founded by his father in 1937. Among his contributions to humankind: a patent titled "Performed pot cover formed of polymeric materials having a texture or appearance simulating the texture or appearance of paper."

The most prolific female inventor alive is biologist Gisela Lorenz, who retired six years ago from the German chemical company BASF. Lorenz has 363 U.S. patents, mostly in the realm of ?"crop protection"-fertilizers and pesticides. Her prolificacy is partly because she oversaw a team of researchers and her name went on patents she worked on regardless of whether or not the main idea was hers. (When reached at her home in Germany, Lorenz said she had no idea she was the leading female holder of U.S. patents.) Two of the other top women are Jennifer Hillman and Olga Bandman, who both worked for the U.S. biotech company Incyte and have 327 and 250 patents, respectively.

Yet such an output among women is rare. A 2006 Harvard University study found that while women are no less inventive than men, traditionally they have not been in a position to seek patents. "For a long time, I was the only woman in the kind of job I had at BASF," Lorenz says. "It's getting better now."

What can be learned from the leading inventors about the origins of their extraordinary creativity? Certainly education plays a role: Most of the chip inventors have doctorates in science and engineering. But, interestingly, none of the group cites degrees as a key. Instead, many talk about the usefulness of a broad education and how it helps them patch together solutions by calling upon their knowledge of multiple disciplines. "My background is in digital electronics and software, but I've deliberately become multidisciplinary-jack-of-all-trades, master of none," Silverbrook says.

Not surprisingly, most successful inventors were born with an engineering mind-set. Most of them were kids who either built things or took toys and gadgets apart to see how they worked. Micron's Salman Akram grew up in Nigeria. His father was an electrical engineer, his mother a mathematician. He says his parents fostered his creativity by giving him parts of toys and encouraging him to improvise. Joseph Straeter, Weder's former colleague at Highland Supply, grew up on a dairy farm, the second youngest of six brothers. He says, "Anything that wasn't worth anything anymore, I took apart."

How do inventors actually think of inventions? Most of them say they first define a problem, then come up with a way to solve it. "I look for something not being done efficiently," says Micron's Leonard Forbes. "I tour around a lot of conferences and keep up on the literature to try to identify problems. I'll go through different approaches. It's not usually an 'aha' moment, but more a process of elimination."

What happens next is the strange, incomprehensible part: finding the answer. Yamazaki says he gets his best ideas after dozing. "Oftentimes, I'll fall asleep while taking the train home at the end of the day," he says. "I wake up, and I have an inspiration."

Mark Gardner, who stopped working for the chipmaker Advanced Micro Devices in 2005, also cogitates while snoozing. "I wake up every day thinking of inventions," he says. "I don't know if it's a curse or a blessing."

Other innovators don't close their eyelids to find inspiration but know that their brains function best when they're not trying to work on a problem. "A lot of times, you don't come up with solutions right away," says Akram. "I keep a problem in the back of my mind, thinking about it in different settings, adding a little here and there. Some of this thinking occurs when I'm on a plane or driving my car." Hearing this, Akram's colleague Warren Farnworth pipes in, "I hate to say it, but there's something about standing in the shower, rubbing my head with shampoo, and I'll go, Wow, why didn't I think of that before?"

Also important is an environment that encourages experimentation. All the men say they have to feel free to propose any idea, no matter how outrageous. "When chasing an invention, you have to not be very critical of suggestions," Weder says. "You have to try not to snicker." Even when the wildest solutions don't work, they can spark discussion that might lead to other ideas. "There are two kinds of supervisors," says Akram. "One says, 'Why are you wasting our time?' The other says, 'This is so cool!'?" Micron's researchers have thrived under the latter.

Then there is another, less romantic reason why these men have so many patents. All work for firms that value patents, systematically and aggressively apply for them, and reward those who win them. At Micron, the patent lawyers' offices are next to the R&D lab, so engineers can stop by and quickly find out if an idea is patentable. Yamazaki and Silverbrook now run companies that essentially produce nothing but patentable technology-and they make money licensing it to manufacturers. In his 24 years at A.M.D., which relies on patentable inventions to compete with archrival Intel, Gardner figures he made more than $1 million in bonuses from his patents.

Which brings up the subject of wealth. It's tempting to think that owning hundreds of patents must be the key to riches, but it's not necessarily true. Inventions created while working for a company usually belong to that company. The leading inventors are all well paid-their firms understand their value-but none is cruising the Aegean on his yacht or lining up to buy the Yankees. Silverbrook has the best shot at great wealth, if his printer technology takes flight.

Silverbrook, Yamazaki, and Weder will continue to chase one another at the top of the list. They each have nearly twice as many patents as the fifth-ranked inventor, Micron's Gurtej Sandhu. They are the reticent megastars of invention, each eclipsing Edison just as Barry Bonds roared past Babe Ruth. These three, especially, deserve a place not just in the popular imagination, but also in history.