The ancient Greeks held that "number rules the universe" and that "God ever geometrizes." Here author Sarah Voss explores the historical connection between mathematics and religion in her provocative book, What Number Is God? Citing many examples, she shows that humankind has long used mathematics metaphorically to understand and make sense of life's most fundamental questions.As Voss shows, contemporary society also uses metaphors of mathematics to investigate such issues, though in a fashion that is frequently overlooked or denied. The intentional use of contemporary mathematical ideas as metaphors for metaphysical notions can have a dramatic impact on modern society, in part by providing new symbols to replace old religious language which has lost its power to excite.