By Matthew Boyle

The Good, the Bad, and the Controversial

With $401 billion in sales from more than 7,800 stores around the globe, Wal-Mart's (WMT) impact and influence over the business world is enormous. Its sales equal the GDP of Poland, and it employs more than 2 million people. The Bentonville (Ark.) retailer is also firing on all cylinders right now, as one of just two Dow Jones industrial stocks to post a gain last year, up 20% to $55. (The other company: McDonald's (MCD).) Here's an unvarnished look at how Wal-Mart got here—the good, the bad, and the controversial.