"Novelists talk about their characters starting to do things they didn’t expect them to. Well, I imagine every writer of biography or history, as well as fiction, has the experience of suddenly seeing a few pieces of the puzzle fit together. The chances of finding a new piece are fairly remote — though I’ve never written a book where I didn’t find something new — but it’s more likely you see something that’s been around a long time that others haven’t seen. Sometimes it derives from your own nature, your own interests. More often, it’s just that nobody bothered to look closely enough."