Bart Ehrman is a scholar of Textual Criticism of the New Testament who was a Christian and then lost his faith and became an agnostic.
He very deliberately seeks to undermine the credibility and trustworthiness of the Biblical text. Some of his books have made it into bestseller lists.
His name is mentioned in this "Index to Islam" because his books are used by a number of Muslim polemicists as support of their attacks on the Bible.
Here we simply want to provide some links to reviews of and responses to his writings, particularly his popular book "Misquoting Jesus".