Joseph Ratzinger, now Pope Emeritus, is one of the most prolific catholic theologians of the contemporary era. He became Professor of theology at the age of 29, the youngest holder of a theological chair at that time. His theology not only draws from biblical-historical sources, but also includes philosophical-cultural ideas and modern scientific disciplines. While many of his books were already translated in various languages, his earliest works, namely his doctoral dissertation on Augustine s ecclesiology and his entire post-doctoral thesis on Bonaventure s concept of revelation, including...