The study deals with Bishop John Milner, the English Catholic polemicist and historian, closely involved in affairs relating to the efforts to obtain Catholic emancipation. It identifies Milner's most fundamental concerns, offering a description of a coherent structure of anti-Enlightenment thought. This description serves to provide a unified interpretation both of his very varied and often influential writings and of his conduct in public affairs in England and Ireland. In this broad perspective, the figure of Milner can be seen to be important for an understanding of the transition being made in his period by the Catholicism of the British Isles to its nineteenth-century identity.