WHEN representatives from the United States and other countries gathered in Evian, France, in 1938 to discuss the Jewish refugee crisis caused by the Nazis, they exuded sympathy for Jews — and excuses about why they couldn’t admit them. Unto the breach stepped a 33-year-old woman from Massachusetts named Martha Sharp.

With steely nerve, she led one anti-Nazi journalist through police checkpoints in Nazi-occupied Prague to safety by pretending that he was her husband.

Another time, she smuggled prominent Jewish opponents of Naziism, including a leading surgeon and two journalists, by train through Germany, by pretending that they were her household workers.

“If the Gestapo should charge us with assisting the refugees to escape, prison would be a light sentence,” she later wrote in an unpublished memoir. “Torture and death were the usual punishments.”