Evangelicals acknowledge the existence of textual variations between biblical accounts of apparently identical events and speeches. They see these as complementary, not contradictory, and explain them as the differing viewpoints of different authors. For instance, the Gospel of Matthew was intended to communicate the Gospel to Jews, the Gospel of Luke to Greeks, and the Gospel of Mark to Romans. Evangelical apologists such as John W. Haley in his book "Alleged Discrepancies in the Bible" and Norman Geisler in "When Critics Ask" have proposed answers to hundreds of claimed contradictions. Some discrepancies are accounted for by changes from the autographa (the original manuscripts) that have been introduced in the copying process, either deliberately or accidentally.