This is the only research on how the Spanish Civil War helped to advance medical progress and what would later be called 'humanitarian interventions'. The Spanish Civil War (1936-39) was pivotal in the history of twentieth-century Europe. However, in many regards it is still marginal in mainstream European historiography. The diplomatic, political, social and humanitarian dimensions of the war are largely unstudied. During the war there were advances in medical care and forms of what we would today call 'humanitarian intervention'. This is one of the first books to carefully study the war from the perspective of its humanitarian interventions and advances in medical services - particularly in the Republican zone. There, international support saw developments in the key areas such as frontline assistance to battlefield casualties, and blood transfusion techniques.