The system of organised Church censorship had its origin during the time of the Reformation in the necessity under which the Church felt itself of protecting the faithful, and perhaps more particularly the doubtful, from the influence of heretical arguments presented in printed form. The earlier history of the Indexes is therefore closely associated with the record of the conflict of the centuries between Protestantism and the Church. This relation has, however, a confusing effect in the attempt to estimate the direct influence of the censorship upon literature, for the reason that the direction of literary activities and the character of literary production were, during the two centuries succeeding the first protests of Luther, very materially affected, outside entirely of the influence of the censorship, by the theological and controversial tendencies of the time. The Reformation was an intellectual revolution, and the contest was carried out on both sides with intellectual weapons. These controversies had the effect of sharpening men’s minds and of cultivating the capacity for thought, for analysis, and for reasoning power. In reading the controversial literature which proceeded on the one hand from such Protestant centres as Wittenberg and Geneva, and on the other from Rome, Cologne, or Louvain, it may well be to-day a matter of surprise that the writers were able to count upon circles of readers likely to be interested in their dissertations and capable of understanding the class of arguments presented. It was the case during the 16th and 17th centuries not only that long series of controversial works were prepared by scholars for the reading of scholars, but that great masses of material, mainly in the form of pamphlets, were placed upon the market for the instruction or the influencing of what we should to-day call the common people. The tracts, “flyleaves” (_flügschriften_), which were distributed from the presses of Wittenberg were addressed directly to artisans, farmers, and peasants. For a few years, the controversial literature of this class was monopolised by the Protestants. The arguments of the defenders of the Church were addressed to the scholars and preachers with the idea of reaching through them the understanding of the common people. Before the middle of the 16th century, however, Catholic writers also began to give attention to the production of controversial literature addressed directly to the common people. The historian who to-day examines the files of this Reformation literature is struck by the high estimate placed by the writers on both sides upon the understanding of these readers among the people. It would be difficult to find to-day among the peasants of Germany, or in the same classes of other countries, any body of readers who would be prepared to interest themselves in thoughtful literature of such a standard, or who would be competent to follow the reasoning and the arguments of these controversialists of