This was the first of two books I read on the Kindle during our trip, and I really enjoyed it. As other reviewers have noted, Norwich doesn't pretend to address theological issue in this book, so the most you get about any particular pope is that they were or were not devout, but for what it is - a secular history of the institution, it is really quite good. His description of Pius XII is a damning one, focusing as it does on the latter's failure to publicly oppose Hitler's campaign to exterminate the Jews during World War II, but he points out things I had not known. In particular, I wasn't aware that German troops actually rounded up Jews in Rome during the War, and Pius said nothing. Norwich also points up the apparent difference between John Paul I and John Paul II, with the former showing indications of being the more liberal pontiff Paul VI wasn't quite, and the latter being extraordinarily conservative.
All is all, a very entertaining book.