According to the National Association of Investors, just one in three Americans feels "comfortable" investing in foreign stocks or bonds.

That, my friend, spells trouble
If this kind of thinking continues, we could be headed for some serious underperformance, if not worse. Or so says the "smartest man in Europe." The smartest who in what?

I know, I said the same thing. But that's what Byron Wien calls him. According to Wien, this mysterious chap earned his title by consistently identifying trends that would have major impacts on global financial markets.

Legend has it, he even predicted the collapse of communism and the dismantling of the Berlin Wall. And yes, he also advised us to start looking overseas for investments long before the bull market in foreign stocks hit the front page.

You think I've lost my mind, don't you?
In my defense, I read this in The Washington Post, and Byron Wien is no hack. He was a top strategist at Morgan Stanley for years. So, I'm inclined to hear him out. As for his "mystery man" on the ground ... who cares? Just look at the numbers.

In 2005, stock markets in countries as diverse as Egypt, Russia, Turkey, South Korea, and Austria all gained 50% or more -- dwarfing U.S. stocks. Just about the same thing happened in 2006, with China leading the charge. I don't know about you, but I sense a trend.

Now, here's the good news: When it comes to making money overseas, we haven't missed the boat. In fact, when Wien last crossed the Atlantic to consult with his "source," he was even more adamant that we move some of our investments overseas. For what it's worth, I'm taking him up on it.

"Global is definitely the way to go"
If you'd rather not trust your money to some "mystery man," how about a Wharton professor? When Dr. Jeremy Siegel met with us here at Fool HQ last year, those were his exact words: "Global is definitely the way to go," he said, suggesting that we should hold as much as 40% of our portfolios in foreign stocks.

I wish I'd listened. I imagine some U.S. fund managers agree. In 2006, the $47 billion Fidelity Magellan fund rode top holdings like General Electric (NYSE:GE) and American International Group (NYSE:AIG) to 7.2% returns. Not bad, until you consider that international stock funds routinely delivered 20%-plus gains, and in many cases much more.

Meanwhile, American institutions such as Wal-Mart (NYSE:WMT) and Home Depot (NYSE:HD) struggled to eke out single-digit gains last year, and mighty Dell (NASDAQ:DELL) didn't even manage that. That's to say nothing of the whooping Toyota has put on U.S. automakers General Motors (NYSE:GM) and Ford over the past five years.

Born on the 4th of July
I assure you: I'm not some doomsayer prophesizing the collapse of the West and the rise of "Chindia." I have too much faith in America for that ... and too much invested here in the U.S. markets.

But I can't deny the fact that more than half the total capitalization of public companies already resides overseas, and that just last year, U.S. investors poured $53 million into foreign large-company funds, up 32% from the year before. And, yes, I'm one of them.

So far, I've settled for the iShares MSCI EAFE Index (EFA). Because I confess: Until recently, I didn't have the guts to invest in individual foreign companies on my own. Now, I have a mystery man on the ground, too -- a Bill Mann, to be specific. If you don't know Bill, he's a longtime Fool and the most knowledgeable expert I know on international companies and markets.  

Need some help, too?
Good news: You don't have to cross the Atlantic for sound advice, either. Bill recently launched an investment newsletter service called Motley Fool Global Gains to help All-American investors like us take advantage of the opportunities overseas. If you already have some experience, all the better. Like I said, Bill's a serious expert. So his advice isn't exactly cheap.

But that's why now is such a good time to get started. Right now, you can sample Bill's advice free for 30 days and pay nothing. If it doesn't help you make money, don't join. You won't pay a cent. As for going broke, if you don't start investing overseas, you probably won't. But it could cost you some serious money.

Why not take Bill up on his free trial offer and try Global Gains instead? You can check out all his past issues and international recommendations, and be among the first to hear what opportunities he uncovers on his upcoming trip to South America. To learn more about this special trial, click here.

This article was originally published on Jan. 17, 2007. It has been updated.

Fool contributor Paul Elliott traveled with Bill Mann on a fact-finding trip to Asia -- so he knows Bill knows his stuff. Paul owns shares of the iShares MSCI EAFE index, but no other company mentioned. Wal-Mart, Home Depot, and Dell are Motley Fool Inside Value picks. Dell is also a Stock Advisor recommendation. You can view all of Bill's top international stock recommendations with your free trial. The Motley Fool has a disclosure policy.