Spanish Republicans and the Second World War tells the stories of the 500,000 Spanish Republicans that fled across the Pyrenees in 1939 as Catalonia fell to Franco's victorious army in the final weeks of the Civil War. Many of the exiles played an active part in the Second World War. Some joined the French and British armed forces and saw action in various theatres including Africa and Europe (both in 1940 and after D-Day).

In August 1944, Spanish Republicans in the La Nueve Company of General Leclerc's Deuxi me Blind e were the first Allied troops into Paris during the liberation of the French capital. Those that had remained in Vichy France were active in the early days of the French Resistance, and Republican Maquis also played a significant part in the liberation of the south-west of France in 1944.

Those who fought the Axis troops in Spain during the Civil War and then again in France assumed that once the Allies had defeated the Nazis, they would launch a military campaign to overthrow Franco's government in Spain. In October 1944, a force of thousands of Spanish Maquis took part in Operaci n Reconquista, the invasion of the Valley of Aran on the Spanish side of the Pyrenees. Their declared aim was to trigger a popular uprising and force the Allies to intervene against Franco's dictatorship.

Whitehead also examines the role of the Spanish volunteers of the Divisi n Azul who swore an oath of allegiance to Hitler and fought with the Wehrmacht on the Eastern Front; the role of the master double-agent Garbo, who played a crucial part in the success of D-Day; the strategic importance of Gibraltar; and the activities of the British diplomatic corps and secret services in resisting Hitler's plans to invade the Iberian Peninsula.