What are the motifs in Poland by James A. Michener?

A recurring idea in this book is the class or societal structure of Polish society. It was more or less rigid with little change in relative structure or position or relationships over the centuries. For the most part, there was a wealthy class and a peasant class without any middle class throughout most of Polish history. The formation of a middle class did not begin until the arrival of the Jews. They basically performed this function in Polish society.