This course looks at the grand themes of the Church—One, Holy, Catholic, and Apostolic—through the themes of the “communio ecclesiology” of Lumen Gentium, understood to be the fullest development of a tradition. Some of those themes are: “Sacrament,” “Mystery,” “body of Christ,” “people of God,” the relation between the universal Church and the local Church, hierarchical communion (collegiality and papal primacy), the nature and mission of the laity, the relation between the Catholic Church and other Churches and ecclesiastical communities, and between other religions (and those not professing one), and finally, between the Church and the world as such.