It took 16 years from first prototype to getting into big stores:

I started working on the vacuum cleaner in 1979. I'd purchased what claimed to be the most powerful vacuum cleaner. But it was essentially useless. Rather than sucking up the dirt, it pushed it around the room. I'd seen an industrial sawmill, which uses something called a cyclonic separator to remove dust from the air. I thought the same principle of separation might work on a vacuum cleaner. I rigged up a quick prototype, and it did.

I became obsessed. It took five years of doing nothing but making and testing prototypes. My wife supported us by teaching art. She was wonderful. But most other people thought I was mad.

When the vacuum was ready, the first thing I did was to show it to the makers of domestic appliances. They didn't want it. I licensed it to Amway in the U.S., which was a disaster. So I decided to become a manufacturer myself. I borrowed $900,000, with my house on the line.

The first sale I made was to a mail-order catalog. I sat with the buyer all day. Right at the end, he said, "It's an interesting vacuum cleaner, but why should I take a Hoover or an Electrolux out of the catalog to put in yours?" I was at my wit's end. I said, "Because your catalog is boring." He called me cheeky—but said he'd take it. And then another catalog took it because I was in the first one. And then I got into one or two little stores.

I usually sell from the point of view of frustration, hoping that other people feel the same way. After that, I was like any other vacuum-cleaner salesman. I showed what it did, why it was different, and why it performed better.

The only way I got into the big British stores was because in 1995, the former British foreign secretary, Lord Howe, came to look around at the factory. He asked if there were any problems. I told him I couldn't get into Comet, which was our equivalent of Best Buy. He said, "Well, my wife's on the board!" The next day, we got a call from the purchasing director. Within a year, we were the best-selling vacuum cleaner in Britain.

James Dyson is an incredibly patient man.