The Wedding in Auschwitz by Erich Hackl
This extraordinary novel is based on a true story of the love between Rudi and Marga. Rudi Friemel fights for the International Brigades in the Spanish Civil War. When the Republican Front collapses, he is interned in France. In 1941, the German prisoners are offered the choice of repatriation, which Rudi agrees to. He and Marga are briefly re-united, and a child is conceived, before he is taken to a Gestapo prison in Vienna, and then onto Auschwitz. Marga and Edi (their son) are left behind in southern Germany. In Auschwitz, Rudi Friemel is privileged. He's given work as a car mechanic, his days are spent servicing the vehicles of the SS. He petitions to be allowed to marry Marga and make his son legitimate. Eventually his petition is granted - no one knows why. Rudi's wife and child are brought to Auschwitz, his father and brother come from Vienna. The officials who normally spend all their time registering the deaths now register a marriage. And the camp band plays.