A couple months ago I read Leonard Vander Zee's book Christ, Baptism, and the Lord's Supper. This was another helpful book explaining the biblical role of the sacraments for the life of the Church. Vander Zee does an excellent job identifying the true dividing line in sacramental theology: the true dividing line in different views of the sacraments is between those who view the sacraments fundamentally as a human declaration to God and those who view them primarily as God's declaration to us. The Reformed position is the latter. In the sacraments it is primarily God who is speaking - speaking to us and about us, identifying who we are, the promises he has made to us, and the hopes we have for the future. I would recommend it. You can find it here.