Ratzinger wrote the book when he was a professor at Tübingen, at a time when Marxist-fueled student uprisings were sweeping across Europe, indoctrinating not only his students but many faculty as well.
Nearly four decades later, Europe appears on the verge of succumbing to what Ratzinger has described as "an aggressive secular ideology . . . which is imposed through politics and which does not give public space to the Catholic or Christian vision." It's amazing how little has really changed.