This chapter serves as a starting point and conceptual background for the book as a whole. It critically discusses the core issue of the historical and contemporary dependencies between immigration and integration policies in postwar Europe, beginning with a reconstruction of the development of the two policies in selected European states. Special attention is paid to the time periodisation of each policy in order to present the dynamics of change in their relations since 1945. The chapter also examines more precisely the development of integration measures in Europe. Several examples are presented to show that integration practices in given European states are shaped not only by different historical, structural or institutional settings but also by dissimilar ideological and political conceptualisations and categorisations of national belonging and social order. Since the growing engagement of supranational entities in the management of the immigration and (recently) integration of migrants is clear to see, we also present the changes in the European Union’s approach to migrants and their integration, together with the respective legal regulations in these domains.