In 1943, Ceija Stojka, then 9 years old, and members of her Romani family were taken by force from their home outside Vienna to a series of concentration camps — Auschwitz, Bergen-Belsen and Ravensbrück. By the end of World War II, an estimated 500,000 Roma and Sinti people — two historically marginalized ethnic groups in Europe — had been killed, alongside millions of Jews and other victims of Nazi persecution. Stojka, her mother and four siblings barely escaped that fate; her father, younger brother and nearly 200 members of her extended family perished. Only decades later, well into her 50s,...