In "Secret History of the Credit Card," FRONTLINE® and The New York Times join forces to investigate an industry few Americans fully understand. In this one-hour report, correspondent Lowell Bergman uncovers the techniques used by the industry to earn record profits and get consumers to take on more debt.

But other consumers, like actor and author Ben Stein, use plastic purely for convenience. While it would appear that Stein -- who says he charges a small fortune every month on his credit cards -- is the ideal customer, in reality, he is what some in the industry call a "deadbeat." That's because he pays his balance in full every month. The industry's most profitable customers, the ones being sought by creative marketing tactics, are the "revolvers:" the estimated 115 million Americans who carry monthly credit card debt.

Ed Yingling, incoming president of the American Bankers Association, tells FRONTLINE that revolvers are "the sweet spot" of the banking industry. This "sweet spot" continues to grow as the average credit card debt among American households has more than doubled over the past decade. Today, the average family owes roughly $8,000 on their credit cards. This debt has helped generate record profits for the credit card industry -- last year, more than $30 billion before taxes.

Some experts say the profitability of credit cards really began twenty-five years ago, when the banking industry successfully eliminated a critical restriction: the limit on the interest rate a lender can charge a borrower. Deregulation, coupled with a revolution in technology that enables the almost real-time tracking of personal financial information and the emergence of nationwide banking, has facilitated the widening availability of credit cards across the economic spectrum. But for some, the cost of credit is often far greater than it appears.

According to Harvard Law Professor Elizabeth Warren, the credit card companies are misleading consumers and making up their own rules. "These guys have figured out the best way to compete is to put a smiley face in your commercials, a low introductory rate, and hire a team of MBAs to lay traps in the fine print," Warren tells FRONTLINE.