With a nod to Elmore Leonard, Bad Paper seeks a bit of love for certain bad or not-so-nice people—the hundreds of debt collectors, some of them ex-cons, who chase down little old ladies on Social Security to cough up their last pennies to pay off the money they borrowed from the likes of Bank of America or Chase. But the marks—who also include the jobless, the mentally ill, and, yes, sometimes, people like you and me—aren’t really paying off the banks. No, the banks long ago sold off these debts to debt buyers like the heroes of this picaresque nonfiction yarn: Aaron Siegel, who is a buyer of