The pastoral constitution Gaudium et spes is one of the most effective texts of the Second Vatican Council (1962-1965), whose impulses continue to have an impact in the 21st century. Gaudium et spes interweaves Catholic doctrine and ethics in a way that cannot be described according to the model of foundation and practical application. Rather, the Pastoral Constitution offers a new grammar of Catholic theology, and the Council's basic pastoral trait finds its strongest expression in Gaudium et spes. At the same time, the text is an ecumenical document of distinction into which suggestions from other churches have flowed and which, for its part, has exerted a strong influence on the ecumenical movement as well as on its social-ethical themes in the past decades. As such, the text is critically appraised and commented on.