Sidney Mermelstein (born Zdenek Mermelstein) is the son of Eliash and Rachel (Frumowitz) Mermelstein. He was born in 1921 in Cinadovo, Czechoslovakia, where his father was a cattle dealer. Zdenek had four older and three younger siblings: Jakob, Ignacz, Abraham, Helena, Esther, Hinde and Ephraim. In the years following the annexation of this region of Czechoslovakia by Hungary in 1938, Zdenek's older brothers were conscripted into the Hungarian labor service. Zdenek's turn came in 1942. He was assigned to battalion 10/4 and for the next two years worked building bridges and bunkers in various locations in Greater Hungary. In October 1944, while working in a town not far from his home, Zdenek escaped. A few days later the area was liberated by the Soviets. Upon his return to Cinadovo Zdenek learned that his parents and younger siblings, Hinde and Ephraim, had been deported to their death in Auschwitz the previous spring. In the course of the next several months he also learned that his three older brothers had survived. Jakob and Ignacz had been liberated in Austria, while Abraham had become an officer in the Czech army. After leaving Cinadovo, Zdenek moved west to the American zone of Germany, where he, Jakob and Ignacz settled in the Gabersee displaced persons camp in Bavaria. Zdenek remained in Gabersee until his immigration to the United States in October 1948. Jakob and Ignacz soon followed him. Abraham, however, was subsequently arrested by the new communist regime in Czechoslovakia. Five years were to pass before he was permitted to leave the country and join his wife and children, who had since immigrated to Israel. With the help of the Red Cross tracing service, Zdenek learned that his sisters Esther and Helena had survived Auschwitz and were convalescing in Sweden. Through them he was introduced to another Auschwitz survivor named Ruth Genuth from Sighet. Zdenek married her in Sweden in 1954 and the following year brought her back to his home in New York.