Five hundred years ago, the church of Jesus Christ underwent a Reformation. The fallout from the Monk, Martin Luther's posting of his ninety-five theses on indulgences was not simply the birth of Protestantism. Luther did not start a new church. Rather, he was trying to reform the church that already existed by reemphasizing its essence-namely, the "good news" (the gospel) that Jesus Christ saves sinners. But, as almost everyone-including conservative Catholics-now admit, the church did need reforming. Some of the issues in contemporary Christianity are very similar to those in the late...