is one of the most important theological works of the nineteenth century written by one of its greatest minds. In this pivotal text, St. John Henry Newman challenges the Protestant claim that many Catholic doctrines are deviations from Scripture, expounding a theory of development of revelation guided by the Holy Spirit. Allowing for organic growth while condemning any progressivist corruption of doctrine, Newman tackles head-on a heated theological debate with eloquence and wisdom, concluding ultimately that such authentic development can take place only within the infallible Church established by Jesus Christ himself.