For years, Edith Eger kept quiet, refusing to speak about the cattle cars or the death camps or the Nazi guard who broke her back. She never told her children how, at 16, she had been forced to dance for Josef Mengele, the “Angel of Death,” who had sent her mother to die earlier that day. Nor did she talk about the death march she endured near the end of the war, and the fact that she resorted to eating grass to survive at a time when others turned to cannibalism.