Several months before Occupy Wall Street, the Nobel Prize-winning economist Joseph Stiglitz wrote, "Of the 1%, by the 1%, for the 1%," an article for Vanity Fair. He returns to the subject in his new book looking at how inequality is now greater in the United States than any other industrialized nation. He notes, that the six heirs of the Wal-Mart fortune command wealth equivalent to the entire bottom 30 percent of American society. "It’s a comment both on how well off the top are and how poor the bottom are," Stiglitz says. "It’s really emblematic of the divide that has gotten much worse in our society." On Tuesday, Bloomberg News reported that pay for the top CEOs on Wall Street increased by more than 20 percent last year. Meanwhile, census data shows nearly one in two Americans, or 150 million people, have fallen into poverty or could be classified as low-income. "The United States is the country in the world with the highest level of inequality [of the advanced industrial countries] and it’s getting worse," Stiglitz says. "What’s even more disturbing is we’ve [also] become the country with the least equality of opportunity."