In 2004, as a precursor to his important book A History of Apologetics, Cardinal Avery Dulles -- one of the great American theologians of the 20th century -- called for a rebirth of "apologetics." Though its specific forms have changed over the centuries, the purpose of apologetics (a technical theological term in Catholicism) has remained constant: to convince those without faith that it is reasonable to believe in God and His Son Jesus Christ.