This chapter presents and analyzes the work of German-Jewish author Ruth Rewald and her social engagement in the Spanish Civil War. Her novel Vier spanische Jungen is one of the few examples of German children’s and youth’s literature about the Spanish Civil War. This chapter recounts Rewald’s volunteer work at the Ernst Thälmann children’s home outside of Madrid, founded by the International Brigades. During her time there, she recorded the life stories of many children living in this home, together with reports on different topics and experiences that she gathered during her visits to a bombed Madrid. This chapter claims that these texts—all found in the German Federal Archive in Lichterfelde (Berlin)—are not just a source material for the children’s novel Vier spanische Jungen, but the novel also commemorates and recounts the stories and fates of the children Rewald met during her time in Spain. Her work serves as a space of memory that speaks to the fate of children in the Spanish Civil War more generally. This chapter tells two untold stories: the story of the author Ruth Rewald and that of Spanish children from mostly working-class families during the Spanish Civil War.