Paul Silas Peterson presents Karl Barth (1886-1968) in his sociopolitical, cultural, ecclesial and theological contexts from 1905 to 1935. The time period begins in 1905, as Barth began to prepare for a speech on the social question (which he held in 1906). It ends in 1935, the year he returned to Switzerland from Germany. In the foreground of Peterson’s inquiry is Barth’s relation to the features of his time, especially radical socialist ideology, WWI, an intellectual trend that would later be called the Conservative Revolution, the German Christians, the Young Reformation Movement, and National Socialism. Barth’s view of and interaction with the Jews is also analyzed along with other issues, such as radical thinking, anti-liberalism, alterity, anti- or trans-historicism, Expressionism, and New Objectivity. The author also addresses specific questions disputed in the secondary literature, such as Barth’s theological development, the place of WWI in his intellectual development, his role in the Dehn Case, his reaction to the rise of fascism in Europe, his relationship to 19thcentury modern liberal Protestantism, his relationship to the Leonhard Ragaz-wing of the Religious Socialists, and his relationship to the Weimar Republic.