Liturgy is concerned with the worship of God. Yet in spite of that - some might say because of that - it is necessary to have rules. It is sometimes mistakenly thought that these rules are archaic and therefore irrevelant; in fact the rules and their interpretation have changed considerably in recent years, so much so that there is now widespread concern among the clergy and church administrators about the degree to which liturgical law is being correctly understood and applied. This study describes and analyzes a wide range of topics in ecclesiastical law. It provides not merely a statement of legal principles, but also a discussion of the relevant law and its developments.