Ellenberg, a mathematician and writer, explains how math plays into our daily lives without our even knowing it. Each chapter starts with a subject that seems fairly straightforward—electoral politics, say, or the Massachusetts lottery—and then uses it as a jumping-off point to talk about the math involved. In some places the math gets quite complicated, but he always wraps things up by making sure you’re still with him. The book’s larger point is that, as Ellenberg writes, “to do mathematics is to be, at once, touched by fire and bound by reason”—and that there are ways in which we’re all doing math, all the time.