Book excerpt: Between ten thousand and twelve thousand Jews tried to escape Nazi genocide by going into hiding. With the help of Jewish and non-Jewish relatives, friends, or people completely unknown to them, these "U-boats," as they came to be known, dared to lead a life underground. Flight and Concealment brings to light their hidden stories. Deftly weaving together personal accounts with a broader comparative look at the experiences of Jews throughout Germany, historian Susanna Schrafstetter tells the story of the Jews in Munich and Upper Bavaria who fled deportation by going underground. Archival sources and interviews with survivors and with the Germans who aided or exploited them reveal a complex, often intimate story of hope, greed, and sometimes betrayal. Flight and Concealment shows the options and strategies for survival of those in hiding and their helpers, and discusses the ways in which some Germans enriched themselves at the expense of the refugees.