This chapter discusses the different options of modern Jewish identities, the theory of ideological change with regard to religious conversion, and the view of modern politics as secular religion. The basic framework of organized Jewish life in the medieval and early modern periods was the local Jewish community, an autonomous legal body that exercised jurisdiction over the Jewish population in a particular geographical area. The logic behind viewing Jews as members of a religion, a component of an identity that is confined to the private sphere of beliefs, was to enhance the assimilation and the acculturation of Jews into German society. Scholars and political theorists long ago noticed the similarities between secular political ideologies and religious ideologies. Scholars have also pointed out that even the aspects of modern politics that appear to be secular are in fact intrinsically theological. The chapter also presents an overview of the key concepts discussed in this book.