argued this decline could be arrested, however, by a revitalisation of belief in Christ and the church. The account of the church in The Spirit of Catholicism differed from neo-scholastic conceptions of the church as an institution and from Protestant understandings of the church as an assembly of individuals. Adam rejected both the First Vatican Council's juridical account of the church and accounts such as that of Friedrich Heiler, who saw the church as "a complex of opposites" united by papal authority. In their place Adam drew on the work of Johann Adam Möhler in describing the church as first and foremost a community, and on Paul the Apostle's description of the church as the Body of Christ. The book also rejects Adolf von Harnack's emphasis on the historical Jesus, emphasising a kerygmatic Christology akin to that of Johannes von Kuhn. Karl Heim, a Protestant colleague of Adam's at Tübingen, responded to The Spirit of Catholicism with a series of lectures that were published under the title The Nature of Protestantism in 1925. George Orwell reviewed The Spirit of Catholicism in The New English Weekly in 1932. Orwell differentiated the book from works of "Catholic propaganda", which focus on the basis of Catholic faith and criticisms of its opponents; Orwell praised Adam, by contrast, for his focus on "what goes on inside the Catholic soul". The book's main significance for non-Catholics, Orwell argued, was as an example of the "Hebrew-like pride and exclusiveness of the Catholic mind". The Spirit of Catholicism has been translated into 13 languages, and was an influence on thinkers including Robert McAfee Brown, Dorothy Day, Thomas Merton, Flannery O'Connor, Alec Vidler, Evelyn Underhill and Pope Paul VI, who drew on it in his papal encyclical Ecclesiam suam. It was one of the most widely read works of German Catholic thought in the first part of the 20th century. Krieg has described The Spirit of Catholicism as "one of the most important studies in Catholic theology during the period between the First Vatican Council (1869–70) and the Second Vatican Council (1962–65)." The Christ of Faith (1954) The Christ of Faith (1954), a collection of lectures, is a comprehensive history of Christology and Adam's final major work. The lectures discuss the sources of Christology and recount the history of controversies in the field, then examine the doctrine of salvation. Here Adam defines Christology as the study of images