Kaminsky bought chemistry books from bouquinistes along the Seine and taught himself to make explosives. But when a man known as Penguin (aka Marc Hamon) recruited him for the Resistance, he wasn’t interested in his knowledge of explosives so much as his knowledge of dyes. The Resistance needed papers for passeurs at the border, for members parachuting in from the UK and for Jews at risk of deportation. Kaminsky proved remarkably resourceful and inventive.