Fluff to distract the holiday-wearied reader? Not a bit: chocolate sales climb 3% annually ($15.8 billion 2005), and that’s a sizable chunk of the candy industry---and Dark is making inroads. Brophy Marcus covers with subject with entertaining clarity and plenty of substance: she brings to bear the pertinent comments of two professors, an alternative medicine consultant, two analysts from Mars (the candy company---no doubt the planet will follow suit in time), three smaller companies and, of course, the ingesting consumer. Unlike the latter after too much indulgence, there’s not a gram of flab in the presentation, which cites---with concise specificity---the findings of no less than three medical studies, which point out the potential benefits of flavanol-rich cocoa products, as well as the well-known deficits. Why the rise? Americans “want better food with more intense flavor”---or their taste buds are wearing out from too much fructose and salt. (The print version underscores that quotation with a witty illustration by Leslie Smith Jr., showing a seven-slot pill dispenser with a different bonbon for each day of the week.) About the only angles Brophy Marcus overlooks are a) that the density of taste in dark chocolate leads at least this consumer to consume less of it, and b) you know there’s a change when Wal-Mart stocks Lindt and Ghirardelli Darks next to their own Sam’s Club bars. This is nutrient-dense and calorie-free reading.