Book excerpt: Poles, Germans, and the Jews themselves were largely unaware, they formed what can aptly be called a secret city. Paulsson challenges many established assumptions. He shows that despite appalling difficulties and dangers, many of these Jews survived; that the much-reviled German, Polish, and Jewish policemen, as well as Jewish converts and their families, were key in helping Jews escape; that though many more Poles helped than harmed the Jews, most stayed neutral; and that escape and hiding happened