Let me tell you about the day I first heard those two words.

It was Christmas 1999. I was on the phone with an old pal. He'd tipped me to a scientist back home who was boasting he could crack the human genome. There was an IPO. I bought.

What the heck is going on here?
Biotech was hot. Genentech (NYSE: DNA) had more than doubled since October. Wall Street darlings from Biogen Idec (Nasdaq: BIIB) to Genzyme (Nasdaq: GENZ) were blowing up. But this was something else.

By New Year's, my genome stock was doubling every week. What gives? Turns out, some Fool named David Gardner had bought it for his real-money Rule Breaker portfolio. In December 1999, I had no idea what that meant, but I was sure as heck going to find out.

By now, you may have heard that Rule Breaker investing is back -- with the original rule breaker David Gardner at the center of it. But it may not be what you think. It's certainly not what I thought it was.

For one thing, it's not all tech
Yes, there was some technology in Gardner's original Rule Breaker portfolio -- including my genome stock. But as it turns out, it was never disruptive technologies he was after so much as disruptive businesses.

To see the difference, think about Wal-Mart. On one hand, Sam Walton was just another retailer. But he was also a man obsessed with raising inventory management to a science. Wal-Mart was a rule breaker, and it paved the way for Best Buy (NYSE: BBY) and Costco (Nasdaq: COST), among others.

So just what makes a Rule Breaker investor?
To find out, I caught up with Gardner and asked him. According to David, "a Rule Breaker is any investor who can embrace the contrary nature of paying up for great growth stocks."

David points out that great growth companies rarely look "cheap" by conventional value investing standards. So you usually have to pay up for them. This can get scary, but he insists that Rule Breakers like these are worth the gamble. Should you take David's word for it? I would.

Turns out, when David shuttered his real-money Rule Breaker portfolio, he'd managed a 20.1% annualized return. That was in mid-2003, after the bear market. Compare that with 9.1% for the S&P 500 and 7.3% for the Nasdaq over the same period. That's the kind of performance that made legends of Peter Lynch and Bill Miller in their day, and rightfully so.

Aggressive growth may not be for you
It can be a wild ride. I learned that when the genome stocks blew up in 2000 and more recently when the Rule Breakers team recommended Affymetrix (Nasdaq: AFFX), another genome stock they sold at a loss.

Then again, Intuitive Surgical (Nasdaq: ISRG) -- a multiple Rule Breakers recommendation -- was one of the top market performers all of last year. It's still up 200% despite the nasty sell-off.

The trick, of course, is spotting companies like these early and having the courage to take the plunge when you do. It helps to get your information from someone you can trust -- someone who has the resources and does the legwork. In other words, not from some wahoo on the phone.

So why not go straight to the source?
If new technologies excite you, and you have the stomach for ultimate-growth investing, consider this: Take a 30-day free trial to David Gardner's Motley Fool Rule Breakers newsletter. You can sample the complete service and see what the team is digging up now. (You can even print out all back issues and check out every single pick in five minutes if you like -- no hard feelings.)

Of course, I can't say you'll get rich quick. But you'll have some fun, learn something new that will surprise you, and get some great stock ideas -- you might even find the next 200% gainer. And since it's free, it doesn't hurt to try. To learn more about taking no-obligation free trial, click here.

This article was originally published on Dec. 16, 2004. It has been updated.

Fool writer Paul Elliott owns shares of Genzyme. Biogen Idec and Best Buy are Motley Fool Stock Advisor recommendations. Best Buy, Wal-Mart, and Costco are Inside Value recommendations. Intuitive Surgical is a Rule Breakers pick. The Fool owns shares of Best Buy. You can view all of David's picks with your free trial. The Motley Fool has a disclosure policy.