Correspondent for The Atlantic and author of a 2002 report on the obesity epidemic ("The Hungry Gene"), Ellen Ruppel Shell explores complicated issues by delving into their history, putting them in a broad social context and delivering the occasional zingy one-liner. "Cheap: The High Cost of Discount Culture" (Penguin Press, $22.95), for example, warns us that "sometimes what looks like a bargain is really just a bad loan." Shell's hard-hitting new book catalogs the consequences of low, low prices: poor-quality merchandise, limited shopping choices, underpaid workers with reduced security, jobs shipped overseas, imported food contaminated with bacteria and factory-farmed fish prone to disease, to name just a few.