The converse of investment and financial porn is debt porn — stories profiling people whose massive debt brings them down. Debt porn pieces usually rely on the confessional first person: "I was a Credit Card Junkie"; "How Red Ink Ruined My Life"; "Debt Cost Me My Home and Family." Debt porn is the credit-card version of confessionals like the movie "Days of Wine and Roses" — or even earlier, "The Lost Weekend."

If "Double Down" and "24/7" are more exciting reads, it's mostly because the stakes are higher. Both books have the thrilling appeal of debt porn, those cautionary magazine articles in which the writer confesses to having thousands of dollars in credit card bills. Readers who dally a bit above their means experience an easy, reflexive sympathy while at the same time vicariously living the cheap excitement of charging fancy dinners, cashmere sweaters and Prada shoes. It's armchair spending.

The best debt porn relies on a first-person voice—'Credit Cards Ruined My Life' (Teen magazine) or 'Confessions of a Credit Card Queen' (Essence)—and a familiar narrative arc: temptation leads to excess leads to a downward spiral of spending, evoked for our disapproving pleasure. Then—wham—rock bottom: she breaks down while forging a credit-card application; he realizes he has never opened half his purchases.