Understanding the Sacraments of Initiation will emphasize the liturgy as an encounter between God and his children in Christ and the Holy The two important points that are stressed in this (1) The liturgy is first and foremost about relationship between God and his people. Sacraments of Initiation will reflect on the image and likeness of God who is himself a community of persons; (2) The liturgy is a language, and the more one masters its vocabulary and grammar , the more one can enter into the spiritual reality and power it makes present.
While it brings together the different sources to present the Church's teaching on the Sacraments of Initiation I don't think it does much other than point out what is already there. It serves as a good introductory text but if you're already familiar with the different sacramental rites you may want to look for something else - again the advantage of this book being that those sources (including the CCC) are woven together