Saville depicts a Nazi-dominated Africa in his second alternative-history thriller, The Madagaskar Plan.

How did you get the idea of setting your series in Africa?

The original inspiration was Philip K. Dick’s The Man in the High Castle, arguably the most famous alternative history of them all. There’s a throwaway line towards the beginning about Africa and the “Nazi experiment there.” That line stuck in my head, and I began speculating about what Hitler might have done if he had conquered Africa.

To what extent do you believe that alternate histories can do more than entertain?

My main purpose was to write a page-turner, something to thrill and hopefully move readers. But I also believe alternative histories can do more. They are thought provoking, by definition. In my book, for example, there has been no Holocaust. What are the implications for history? Counterfactuals can also offer a moral justification for real events. My world has the United States remaining staunchly isolationist, and we can see the consequences. But this is not just about looking back to the 1940s; it has significance with America’s role in the world today, as the U.S. becomes wary of engaging in conflicts that could potentially benefit those involved.

What sources did you use?

The Madagaskar Plan is about the Nazi scheme to deport the entire Jewish population of Europe to Madagascar. Prior to the Holocaust, this was to be their fate. My primary sources for this plan were a series of top-secret memoranda that passed back and forth between the German Foreign Office and SS. These circulated at the highest level and were overseen by Reinhard Heydrich and Adolf Eichmann, one of the architects of the Final Solution. The memoranda discuss everything from the number of Jews needed to be shipped from Europe each month to the establishment of an internal Jewish police force to help the SS control the island.

Why make Dunkirk the point of divergence from reality?

Many readers think that Dunkirk is the point of divergence, and although it’s true in the geopolitical sense, to me it’s a symptom of a much earlier deviation from history. The true divergence is more subtle and comes before the Nazis have even taken power. History is not decided by headline events, or the outcomes of battles, but in the obscure moments of our personal psychology. We make seemingly unimportant choices and these ripple through time in ways we can never imagine, informing much later decisions that can have profound effects on the world. Though I should add, you don’t have to read the book that way!