“Iota Unum” is one of the best books I´ve ever read. It was difficult getting into, and at first it made my head ache. However, once I got used to the high intellectual tone, I loved it.
The best thing about it is that it uses official sources, mainly the Osservatore Romano, to highlight the contradictions in doctrine between pre and post VII teaching. It would be unfair to say that he attacks the Papacy, as many have claimed. In fact, Amerio is one of the best allies the Papacy has had during the 20th century. If to point out error in charity is a good and catholic thing to do, Amerio´s book is 100% catholic.