This is an exhaustive study of the life of Philip II and his times, with a lot of attention to his dealings with England, the Vatican, France, and Holland (which was then under Spanish rule). Walsh is a careful, excellent writer and historian. He makes the 770 pages, well, not exactly fly by, but not drag, either. He is thorough -- Walsh thoroughly documents his corrections of other authors' claims about Philip II.
For this general reader, there was really a bit too much correction (I don't know who these other historians are and I don't really care what they said about Philip), but Walsh wasn't writing this for me. Similarly, there are a lot of names and battles and things that just kind of flowed over my too-brief attention span. But this book gave me a respect for Philip as well as the sense that I understand him as a person to a good extent.
He was first and foremost a Catholic, and saw his role as the king of Spain as the guardian of the Catholic Faith. Walsh doesn't shy from showing how this sometimes caused him to clash with the Pope because Philip saw what was best for the Catholic realm of Spain as best for Europe (Kind of like a Spanish, Catholic version of L'État, c'est moi, Louis XIV is alleged to have said.) And it's not really clear that Philip was wrong -- the almost universally misunderstood Inquisition actually kept Spain in good spiritual health. Many history books overlook the appalling bloodshed caused by the Protestant revolution, often undertaken by its supporters (Jews, freemasons etc.) who were simply anti-Catholic and not themselves motivated by any faith. If Walsh were writing today he would probably be called anti-semitic (as Philip has been -- though Walsh gives plenty of examples to show that he wasn't against Jews, but against those who tried to tear down the Faith.
The last chapter is kind of an overview of Philip's life as monarch and his slow, agonizing approach to death. It is moving. He suffered much, yet his faith brought his much peace at the end.
There is so much else to discuss -- 770 pages covers a lot of ground! -- but this is some of what I appreciated about this biography.