The story of the Italian resistance is one of the epics of 20th-century history: from September 1943 to April 1945, Italian partisans in the north fought a guerrilla war against German occupiers. Nazi troops had rushed south to occupy Italy when, after Mussolini’s arrest in July 1943, the new government declared that it was now siding with the allies, not the axis powers.

The German reaction was ruthless: they killed 6,000 Italian soldiers of the Acqui division in the Cephalonia massacre and more than 1,000 men in sinking the Roma battleship. Nazi paratroopers rescued Mussolini from his mountain-top prison and installed him as a puppet head-of-state in the so-called Salò republic on the shores of Lake Garda. That meant the partisans weren’t only fighting a war of liberation against foreigners, but were one side of a brutal civil war between Italians: as the allies laboriously advanced from the south, the partisans – poorly armed, ill fed and often freezing in mountain hideouts – were taking on the die-hard followers of il Duce.

Although it’s a well-known story, it has rarely – outside Italy – been told from the viewpoint of the women involved. Caroline Moorehead does so through the intersecting lives of four female friends in Turin who became staffette (couriers) in the resistance, delivering intelligence, letters and weaponry: Bianca (a communist law graduate and factory agitator); Silvia (a doctor); Frida (a literature graduate); and Ada (the widow of the anti-fascist Piero Gobetti).

Two of the women were from the Waldensian community (Italy’s centuries-old Protestant minority) and two were in stable, but unmarried, relationships. Ada and Silvia were both mothers. They had strategic advantages over male partisans: used to being invisible or underestimated, the women were in some ways natural clandestines. “You could be anybody. You were a fire without smoke or a flame,” one recalled. Troops at checkpoints often ignored prams or shopping as women’s natural baggage, not realising they could be the disguise for contraband. Their transformation from studious, dutiful daughters into daring, scruffy, exhausted combatants is brilliantly and subtly told.