Phillipa Gregory thoroughly researches her books, so even though they are fiction, they are a good reflection of the time period she is writing about. The Red Queen tells about how Henry VII's mother worked to get him on the throne. We thought political intrigue and maneuvering was something that just happened in our time. The things that happened in the 1400's make some of the stuff happening today look tame.
You have to be a lover of historical fiction to enjoy Phillipa's books. But if you do, you are in for a treat of well-written, well-researched books.