Shortly after the Nazi seizure of power in Germany in early 1933, Karl Barth penned Theological Existence Today, an emergency pamphlet for German churches, pastors, and theologians. In response to the nationalist authoritarianism of the new regime, Barth urged the church to return to the "heart of the matter" by focusing in the first instance on the responsibility to bear witness to the Christian gospel. Only by prioritizing its allegiance to the triune God of the gospel could the church offer resistance in the political sphere. Tacitly here, Barth argues that the rise of Nazism constitutes idolatry, for, by demanding that all German citizens swear their allegiance to Hitler and the party, the regime had effectively displaced true Christian worship with acquiescence to a false god. This is the first English translation of this seminal text since an initial, hastily produced translation from 1933. It is presented here along with three other key texts from Barth's struggle against Nazism, including a new translation of the Barmen Theological Declaration. In a world witnessing yet again the rise of Christian nationalism, these essays have immense relevance to the theological task in our own day.