There was a day when the plausibility of Christianity was debated on a philosophical and metaphysical basis: Does God exist? Can a good God create and sustain a world marred by evil? Can peoples in all times and places take seriously the very particular claims made by and for Jesus Christ? Today Christianity is often challenged not from philosophy or metaphysics but from history. Rather than attack the supposed proofs of God's existence, skeptics of all sorts (college professors, journalists, members of ethnic minority groups, women, and especially Generation Xers) are more likely to point to...