I'm not going to get into what's really true in this book and what isn't. Honestly, I'd have no right to make the judgement, since Tudor England isn't something I know all that much about. Maybe Henry VIII really did have this many mistresses and bastards, but I'm not going to judge that.
I do wonder why Mary was considered a bastard after her father divorced her mother. They were married at the time of her birth, and that should be enough! It's not, but I find it confusing.
I didn't really like the set up of this book, since each chapter was focused on one mistress. Some focused more on the wives or the children, but the idea is the same. It was really odd to read about an adult Elizabeth I or Mary I, when they hadn't been born yet (since their mothers hadn't come up yet). I would have liked this book a lot better if it had been in chronological order, but that might have been confusing too. You just can't win