Morduch and Schneider carried out a fascinating research project: they and a team of associates worked with more than 250 U.S. households over a year collecting detailed information about how much they earned, how much they spent, and why they made the decisions they did. What the authors found was that income for lower- and lower-middle-income households often varies from month to month, and those variations are responsible for much of the emotional stress and economic difficulty such families experience. For retail workers whose hours and schedules change, or waiters whose tips go up and down depending on the season, or sporadically employed people who endure gaps between temporary jobs, the erratic nature of their income compounds the problems of poverty. The book’s portrayal of its subjects often seems too earnest and one-dimensional: the poor are always sincere strivers; big corporations are invariably greedy. If there were any alcoholics or drug addicts among the families who blew their money on substance abuse, the authors don’t tell readers. The book recycles and repeats its core ideas more than needed. Nevertheless, its main point is important and holds up well: policies aimed at alleviating poverty need to look harder at increasingly erratic income streams.