Seventeen times per day, Muslims pray that Allah would keep them from going astray--in the way that Christians have gone astray. But have they? Rather than portraying Jesus Christ as an imposter who claimed to be divine, Islamic theology presents Jesus as a mortal prophet who served his generation as other prophets did their respective generations. Since Christians believe the biblical narrative that Jesus is Lord, God, and Savior, it is not surprising that the standard Islamic narrative asserts that Christians have gone astray. In fact, if Christians are correct in their beliefs, then the advent of Muhammad, and the religion of Islam itself, are unnecessary to God's cosmic history. This book probes deeply into the extremely urgent--but often unasked--question facing Muslims regarding when, where, and how the main body of Christians may have gone astray.