Mimi Schwartz's father was born Jewish in a tiny German village thirty years before the advent of Hitler when, as he'd tell her, "We all got along." In her original memoir, Good Neighbors, Bad Times, Schwartz explored how human decency fared among Christian and Jewish neighbors before, during, and after Nazi times. Ten years after its publication, a letter arrived from a man named Max Sayer in South Australia. Sayer, it turns out, grew up Catholic...