Liturgical and theological history overview for a basic understanding of the essential lines of development from early Christian times to the present. Detailed commentary on the individual procedures according to the current basic order. Comparison of the "ordinary" form of the Roman Rite with the extraordinary form (Tridentine Mass) and the Divine Liturgy. Outline of a theology of the Eucharist based on the mission of Jesus, dogma-historical disputes, and systematic reflection. Interdisciplinary, cross-sectional focus in accordance with the organic unity of liturgy, liturgical history, theology of the liturgy, biblical theology, dogmatics: Trinitarian theology, Christology, Pneumatology, Ecclesiology. Help for thoughtful understanding.