This article provides an overview of Böckenförde’s writings on issues of religion, ethos, and the Catholic Church in relation to law, democracy, and the state. It presents Böckenförde as an inner-Catholic critic, who attempted to persuade Catholicism that one’s own freedom can be defended only as part of the general freedom. This was finally achieved, at least dogmatically according to Böckenförde, with the Declaration of Religious Freedom at the end of the Second Vatican Council. The article lays out how Böckenförde sees the role of religion and natural law in secular democracy, namely as one informing the citizens’ ethos. Democracy cannot survive in the long term unless it is carried out by people who consider themselves part of the same demos and work towards a shared democratic culture. The article includes information on his intellectual biography, a periodization of his academic writings in seven phases from 1957 to 2012, a discussion of some of his core arguments as an inner-Catholic critic, a reflection on the cover images he chose for the two volumes, and closes with concluding remarks on Böckenförde’s view of religion in democracy compared to other theorists of democracy and secularism.