(FORTUNE Small Business) – When Scott Cook was trying to decide whether to take up entrepreneurship, he surveyed hundreds of people who had started their own businesses. Their advice: If he decided to do it, he should fashion himself into an industry-inverting visionary. Okay, so it didn't quite happen that way. But with Cook, who in 1983 co-founded software giant Intuit, it seems that just about every eureka moment he's had has been buttressed by rigorous testing. Such meticulousness reflects Cook's training: He spent several years as a marketer at Procter & Gamble, where "they taught us to understand the customer."

Determined that Intuit, now a $1 billion publicly held business, would follow that principle, Cook didn't act on his original hunches until he had talked to hundreds of potential customers. That research convinced him that there was indeed a market for money-management software, provided it was streamlined and simple instead of loaded with complex features. How right was he? By 1994, Intuit was poised to merge with Microsoft, a marriage the Justice Department ultimately scuttled. "I thought it would be exciting in some ways, but I probably wouldn't be with the combined company now had that happened," Cook says. "Founders have not done well when acquired by big, centralized companies like Microsoft."

Of course, Intuit itself has become a giant company, and Cook has adjusted his role accordingly, bringing in an outside CEO in 1994. "I recognized my skill set was holding the company back," says Cook, now chairman of Intuit's executive committee. To this day, he remains a believer in the all-too-rare art of listening. "It's amazing what people will tell you," he muses. What's equally amazing is what Cook has created by hearing them. --Joshua Hyatt

"I would describe the start of Intuit as more of a eureka insight than a moment. The moment is really just the beginning of a journey and, in fact, only a way station on that journey. But the centerpiece of it is an insight that challenges the common wisdom. It's when you implement that that you end up revolutionizing an industry.

Most of our major businesses at Intuit are based on a eureka insight. Quicken was the first of those. It really came from two separate insights at two separate times. The first was when my wife complained about doing the bills, and it was her complaining about the bills that caused me to say, 'Ding! This would be a great use for the computer.' I thought that because of the inherent nature of the work and the inherent set of things that computers are good at. However, that was not a unique insight. There were a lot of other people who thought computers might be good for doing personal finance. In fact, when we launched Quicken there were roughly 25 other personal-finance products on the market. So the idea of using a computer to do finances was not novel, even in the very early days.

I had always toyed with starting a business. When I was in junior high I sold Christmas cards door-to-door to earn money. And in high school I looked at going into the cuff-link business. In college, at the University of Southern California, I ended up running a club that was really more like a business. In two years I took the ski club from having no leader and being bankrupt to being the largest campus organization at the university. When I was a consultant [at Bain], I toyed with the idea of going into the windsurfing travel business. With a buddy of mine, we ran the first--to my knowledge--windsurfing package tour in the U.S. It was a great success. But it was not a business that appealed to me. It looked as if it would remain a boutiquy, small custom business.

At about the same time, though, I listened to my wife's complaints about doing the bills. So the first of the two eureka insights was, 'Oh, wow, this is a good use of a computer.' Computers could do this job well, whereas a lot of jobs that people were alleging computers would do well, they were actually poor at doing. Storing recipes was a truly stupid use of a computer. There were a lot of really bad ideas proposed for the use of computers by people who were noninsightful. What are computers best at? Numbers and data storage. And finance is all about numbers and storage, plus there's a high degree of repetition. The bills you pay go to the same people every month, in general. So once you've typed it in, you don't have to retype it.

But having the insight that finance is a good use for a computer was not the key to success. The key was the second insight I had, which came about from surveying customers. I got the phone book, called up households, and tried to understand what they did in their finances--their likes and their dislikes. I picked mostly upscale neighborhoods, the kinds I thought would have computers at the time, which was 1982. And the insight that came out of that was that people weren't turned on by doing graphs or other fancy stuff. They just wanted to get the work done, and they wanted to do it as quickly and easily as possible. None of the software products on the market were designed to do that. They offered a huge amount of complexity, rather than being optimized for speed and ease. There was a whole belief that the more features you had, the better. The industry paradigm was wrong for this segment, for this purpose, for what customers wanted in personal finance.

Yet the products in the market did sell. In fact, the most complex ones actually tended to sell better. This seemed incongruous; something didn't fit. So the only way I could get to the bottom of that was to actually interview customers who were using the personal-finance software products. The companies in the industry wouldn't give me their names, of course. So I wound up calling people in the computer industry to find those who had tried personal-finance software. I called computer stores and I called people at computer magazines. Sixty-five percent of those in the computer industry whom I interviewed had tried personal-finance software. And 61% had tried it and quit. I asked, 'Why did you quit?' And the answer was 'It was too slow, too hard.'

So we made Quicken fast and easy. The catch is, if you're going to make it fast and easy, it's got to be fast and easy in the hands of the customer, not in my hands or an engineer's hands. We were the first to do usability testing of any kind of PC software. We would just bring in people and have them use prototypes. We didn't tell them how to use it. We just watched. And that would tell us what wasn't working, what wasn't obvious. Then we'd go back and fix it, and then retest it. It's that second insight that made Quicken dramatically different from the other competitors, which is why it became huge and the other ones have died.

But we almost failed twice. When we went out to get venture capital, in the first half of 1984, we totally struck out. We were looking for $2 million. I couldn't get anyone interested because we flew against the entire paradigm set. First of all, they didn't believe that consumers would buy computers. Second, even if someone believed consumers would buy computers, they didn't believe that consumers would do their finances on computers. Third, even if you got someone who could believe those two things, no one believed they would do their finances with us, because they believed that having more features was the key to success.

Here we were, doing a simple version. And the investors couldn't point to anyone who had succeeded with our strategy. Every one of them passed. But that's what typically happens if something is truly a major eureka. It means it's a different mindset--not merely an extrapolation of what other people have already done. So most people think it's wrong, or if they don't think it's wrong, they think it's unimportant. That's why we couldn't raise any money. By this point I had spent all the money I'd saved. All totaled, with the money from my parents, we'd gone through about $360,000.

One of the guys in the company said, "Hey, it's clear this VC thing isn't working. Let's go talk to some rich people." I didn't know any rich people. But he knew two. We went and talked to them together. We got $151,000, and that kept the doors open for another six months. Then we almost went out of business a second time. We'd been selling Quicken to banks, which would resell it to their customers. After we sold to the first two banks, we ran out of money. We had to stop paying salaries. And it became clear that banks couldn't sell the software. There went our sales channel, and half of our people had left, three out of seven. They had to find jobs that actually paid money. That was in 1986. We finally put everything we had into selling at retail, and fortunately that worked.

I contacted a friend whom I'd met in the industry. He went and personally sold to the first distributor. It was a very small distributor, and because of this personal relationship my friend got him to accept it. Then I found out that a guy who had once tried to hire me was now the head of sales for a distributor. He knew I did good stuff. So he stuck it in their catalog. Then it was my job to create demand. Word of mouth turns out to be the best way to do that. And it worked for us.

Today Quicken is just 5% to 7% of our total revenue. The rest comes from other eureka insights. One came out of another quandary. We sold Quicken, and we were surveying our customers, and one of the questions was, "Do you use Quicken in the home or business or both?" It turned out that half the customers used it in business. At first we ignored that. Another year and a half went by. By 1988 we had a couple more surveys that showed the same thing. It finally dawned on me to ask, "What's going on?"

So I called up some of the businesses and asked, "What are you doing? Why are you using this instead of using accounting software that was specifically designed for business?" Based on those results we did a randomized set of calls to small businesses--in other words, not just to our customers. The eureka insight we got from that was that if you have a company of 15 people, you don't have room on the payroll for a trained accountant. So the person who keeps the books is somebody else--it could be the owner, the owner's spouse, the office manager. And the vast majority of these people don't know debits and credits, and don't want to learn. So we actually built a product for businesses.

After two years of development, we launched QuickBooks in March 1992. Just four months after launch, we got data that showed that QuickBooks had become the clear market leader. When you do something that's truly revolutionary, something that's truly one of those major paradigm shifts that come from eureka insights, it delivers as long as you execute really well. Most of the competitors will never copy it--they won't even understand it--and they'll go out of business. The eureka insight can be that powerful. And this company is still a place where people who have eureka insights can make big change happen. We have a tradition of eureka here."