Although dependence upon a literally inspired Bible has been one of the most common beliefs among American Protestants, theological justifications for this doctrine of the Scripture have not been common. Eighteenth century infidelity from Thomas Jefferson to Thomas Paine attacked the possibility of special revelation more than any particular form of revelation. In order to refute these adversaries, the great champions of orthodoxy, such as Timothy Dwight, never found it necessary to become specific about the nature of biblical inspiration. The growing influence of biblical criticism after the Civil War ended this period of Edenic innocence and compelled the churches to theologize about the nature of biblical authority. The results were not unanimous, and the ensuing controversy focused attention as never before upon the doctrine of inspiration. Only one of the conservative defenses of inspiration, the Princeton Theology, will be discussed in this paper, but there are good reasons for considering it the most influential theological support for biblical literalism in the twentieth century. J. Gresham Machen carried the Princeton Theology with him into his new denomination and seminary after 1929, and others in Bible institutes and seminaries not connected with the Presbyterian church have looked up to the Princeton professors as their great teachers and champions. In the Fundamentals series published just before World War I, six articles were devoted to the problem of inspiration, and three of these took much of their argument from the Princeton Theology. The history of the Princeton Theology is not well known nor its importance widely appreciated, but some good monograph and periodical literature has been written.