I was sad to see some of them go. Like a magic lantern that would project images on walls and people would travel the countryside with these magic lanterns and tell stories. And there was this cabinet that you would walk up to and it had a little peephole and inside the whole thing was covered in thousands of little mirrors.

I had all these sparkles I'd collected and wanted to work in, but when I originally started writing it and it was originally this novel about all these people set in 1666, what I was so interested in was the New Science.

The reason the middle section switches to third person is, well, this is middle age. This is the part in her life where she loses track of something that was driving her and has to figure out what's going to drive the next part of her mission, this mission to be an author. I had to push back away from her for a while before we could come up to that really lyrical close third in the final section.

Margaret Cavendish was one of the people who came up in the course. That was when I started thinking about her as a character for a book, but my idea was for a totally different book. It had all these characters in it; Samuel Pepys was one of the main characters. He famously wrote these extensive diaries through the period that are really funny and sort of saucy, actually.

I can be a fairly hands-on editor, and when I'm editing someone I feel intensely invested in that writer and her work. I love helping to shape a book, and I feel very privileged to get to do that with writers I'm excited about. I think doing that work for the past six years has changed me, and it better prepared me for the questions and suggestions.

The way I've talked about my research process is that it was like magpies. I was just sort of moving through all these books and when something shiny would pop out I'd be like, Ooh, I love it! and I'd pluck it out. It's fun to figure out how to use those bits you really love - like I'd read about gold shoes with cork heels. Obviously, Margaret would have to wear those shoes.

It's all just so fraught when you're writing and then going through the editorial process. It feels like this shape-shifting thing. When it's done, and you can't change a single word, it's a totally different thing. I was surprised by what that thing was.