There are seven sacraments administered in the Catholic Church. What are they, and what do they do? Why do human beings require sacramentalized, visible realities to seal their confession of faith in Jesus Christ? Why does the Catholic Church administer the sacraments in the way that it does? Leading Catholic theologian Romanus Cessario, OP, offers an in-depth explanation of the seven sacraments celebrated in the Catholic Church. He addresses the rationale for the sacraments and provides detailed exposition of each one, highlighting the importance of the Catholic tradition--and of Thomas Aquinas, in particular--for contemporary reflection on the sacraments. This book examines why participation in the sacramental life of the Church is required for the believing Christian and helps listeners understand the role the sacraments play in the sanctification of the world.