Millions of Americans work full-time, year-round, for poverty-level wages. In 1998, the author decided to join them. She was inspired in part by the rhetoric surrounding welfare reform, which promised that a job, any job, can be the ticket to a better life. But how does anyone survive, let alone prosper, on $6 an hour? To find out, she left her home, took the cheapest lodgings she could find, and accepted whatever jobs she was offered. Moving from...