Baxell described the book as "the first to place the Spanish Civil War within the context of the volunteers' lives, rather than the other way round"; and seeks to deliver its narrative "from the perspective of the participants themselves using, wherever possible, their own words". Set against the context of the 1930s in Britain—marked by the Great Depression, the growth of the Communist Party of Great Britain (CPGB) and the emergence of Oswald Mosley's British Union of Fascists—the book primarily deals with the International Brigades and their volunteers, but also covers those who were involved in other capacities, including George Orwell who fought with the POUM, British journalists who worked in Spain during the Civil War, and the small number of Britons who fought on the side of Francisco Franco. Baxell describes the May Days of 1937 in Barcelona and British participation in the Siege of Madrid and the Battles of Jarama, Brunete and the Ebro. He continues by describing the experiences of the British volunteers who departed Spain at the end of the war and those who were taken prisoner, and Civil War veterans' experiences of the Second World War. These included Tom Wintringham who helped to found the Home Guard and Bernard Knox, who joined the Office of Strategic Services.