I had Nickel and Dimed one on my 'to read' list for a long time, after Adam originally recommended it to me. It's an illuminating, if somewhat depressing read.
The author spent a year doing a stint of low-wage jobs in a number of cities around the country, trying to see if she could support herself on a minimum wage job. She spents time working as a waitress, a cleaning lady, a Walmart clerk, and a number of other positions, sometimes working two jobs while also apartment hunting or dealing with other administrivia.
What she finds isn't surprising; that people earning the minimum 'living wage' in this country can get by, barely, often by leaning on friends and family to share rent and the like, and that any moderate expense (e.g. a medical one, or a car repair, or first/last months rent on a new place) can start a snowball effect toward homelessness pretty quickly.
What's maybe more illuminating (not in the sense that we didn't know, but that it shone light on what we like to keep in the dark), is that it's not that the so-called working poor are lazy or stupid. Rather, they are subject to a system that bleeds its poorest dry. The flipside to the rich-get-richer is of course that the poor get poorer.