Sacramental Theology. A General Introduction
by Kenan Osborne, O.S.B.. This was one of the required texts for my Liturgy and Sacraments class in the Spring 2015 semester at the University of Dallas. This is a very readable book despite its deep content.
The author explains contemporary Roman Catholic teaching on Sacramental Theology, relying on the documents of the Second Vatican Council and the writings of Karl Rahner and Edward Schillebeeckx. I liked the description of the Church as a sacrament of Jesus (page 89):
When I, as an individual Christian, say: "I belong to the Church," this challenges me to say in a clearer way: "I am part of the Church" only when I reflect Jesus.
I highly recommend this book to anyone who wants to learn more about how the Church looks at the sacraments.