A nonfiction book, especially if it’s on a complicated subject, must have a dramatic structure. If you’re writing a novel, the author has the advantage over the reader because the reader doesn’t know whether this figure’s going to be a hero or a villain, so you can do what you want with him. But if you’re writing a nonfiction work about famous and important people and about the major events in history, people know how it turned out. They know that Michelangelo was a great painter and that Picasso was going to one of the most famous painters in the world and so on. So the writer has to create what I would call a willing suspension of knowledge and make a drama of the facts of the past.