Excellent book, also the little knowLudwig Ott, Fundamentals of Catholic Dogma. It dosn't get much clearer than these.
There are more up-to-date editions. The one pictured is from 1908! Denzinger-Schonmetzer has an edition dated 1963. There are also available other later editions which include dogmatic constitutions of Vatican II and the popes since John XXIII.
And, based on the latest document out of Rome, "one book that every Pope needs to read." I say this because the Enchiridion gives answers in black and white - not the grey of the Jesuits which permeates "The Joy of Love".