This text covers changes in the Mass since publication in 1971, including the 1985 reprint revisions (notably Eucharistic Prayers and Eucharistic Prayers from Masses with children). It also describes the rites of the Church in the context of their theological and historical background and in relation to pastoral practice. It is aimed at theology students, students on liturgy courses especially those following the syllabus for liturgical formation issued by the Liturgy Office and all those seeking a deeper understanding of the Mass.