This series contains materials related to San Francisco-based anti-fascists who fought in the Spanish Civil War as part of the International Battalion the Abraham Lincoln Brigade (ALB). It includes the letters that fighters in the ALB wrote from battlefields of Spain to their friends back home in the San Francisco Bay Area, detailing their experiences, political convictions, and reflections on the nature of warfare. This series also contains materials related to the Friends of the Abraham Lincoln Brigade, a group which advocated for the fighters of ALB by publishing their letters in newspapers such as People's World and original pamphlets, sending gifts of cigarettes and gum, and garnering political support for the cause of international anti-fascist solidarity. Also present are materials created by the Veterans of the Abraham Lincoln Brigade, demonstrating the efforts of surviving members to commemorate this history and engage in continued international solidarity struggles.