The Civil war fought in Spain between 1936 and 1939 was one of the most bloody and bitterly fought military campaigns of the 20th century. Both the loyalist Republican troops and the Nationalists under General Franco used foreign volunteers to supplement their own forces. In the case of the Republicans the Comintern organised the International Brigades, eventually recruiting over 40,000 people. The International Brigades were the Republican forces elite and as such were stationed at the toughest sectors and often led the most desperate attacks. Ken Bradley details the history, recruitment, composition, organisation, uniforms and equipment these brigades.