They are all set in the same alternate history. Each of them features the same detective, Carmichael, in alternate third-person chapters, and a different first person female narrator.
In this universe, Britain made peace with Hitler in May of 1941, at the time of the Hess mission, at a time when the US was showing no indication of joining WWII and when it was apparent that Britain could not possibly defeat Hitler alone. In reality, the Germans were completely bemused as to why Britain wouldn’t accept their repeated peace offers, because it made no sense to keep on fighting. There are ways in which the Small Change universe is more plausible — if also more horrible — than real history.
I wrote Farthing first, very quickly, and then the other two books arose out of post-Farthing research. Farthing was intended to stand alone, but when I thought of sequels I thought of both of them. There was one book, and then there were three.
Nothing is written in a vaccuum. I wrote these books during a dark time politically, when the US and the UK were invading Iraq without a Security Council resolution on a trumped up casus belli. I was brought up by my grandparents, and the defining event of their lives was WWII, it cut across them like a knife. To find a government I had voted for waging a war of aggression really rocked my expectations. If I’d been in Britain I’d have marched and protested, but I was in Canada, which kept out of that unjust war. My husband is Irish, and Ireland wasn’t doing it either. I think it was my isolation on this that went into writing these books.
I had read a lot of cosy mysteries, Tey, Sayers, Christie, Heyer, and considered the interesting fact that they were about sudden violent death and yet they were written in a way that made them safe, indeed cosy. I thought I could use this to write about fascism, and not in a closed known historical context where we’re safe and sure of the ending either.
The Small Change books are about how people do bad things — how we do bad things, and allow them to be done in our name.
It’s easy to look at the Nazis and say they were monsters, at the concentration camps and imagine ourselves the victims. Looking at how real people come to the position of doing and allowing these things is much more uncomfortable.
I’ve always been a cheerful and optimistic person, and that’s why I wrote these books.