Sister Queens: The Noble, Tragic Lives of Katherine of Aragon and Juana, Queen of Castile by Julia Fox (nonfiction)

These sister queens are Juana of Castile and Catherine of Aragon.  Mary Todd Lincoln has been in the press lately because of her mock re-trial for insanity, but Juana remains the most egregious use of that charge by men who want to take over the wealth of the woman in question.  And we all think we know what happened to Catherine.  Ms. Fox alternates between the sisters throughout a timeline, articulating new interpretations of their motives and experiences.  I loved this book.