قانون الإيمان
Originally published in German in 1968 under the title, "Einführung in das Christentum", Ratzinger restates the Apostles' Creed and the meaning of this foundational text in language that has a greater contemporary resonance than the Creed itself. Like the Apostles' Creed, the book presents the doctrines pertaining to the Father, the Son, and the Spirit in sequence.