My gradual descent into a life of crime began a long time ago, when I was working at the Château de Breteuil, southwest of Paris, and asked the marquise: 'Who is the beautiful woman in that painting?' She turned out to be one of the best-known of that already famous family. Born Gabrielle-Émilie le Tonnelier de Breteuil, she became Marquise du Châtelet, a physicist and mathematician, and translator into French of Isaac Newton's Principia Mathematica. She also lived with the notorious and fascinating poet/philosopher Voltaire at her Château de Cirey in the Champagne countryside.

I read their letters and works, researched their lives together and, very much later, visited Cirey. Since then I've written a great deal about them – but this is the first novel I've released in which they appear. Why a crime novel? Du Châtelet's and Voltaire's lucid observation of life, the universe and everything convinced me that, if a military police investigation were mounted on their territory, they'd react in ways no one could ever predict. Especially if Voltaire were first suspect ...