This book contains the results of a first attempt at assessing the impact of complex diversity on the realm of language politics and policies, and at analysing how the legacies of the old interact with the challenges of the new in this realm. While an initial round of activities in the Research Networking Programme Responding to Complex Diversity in Europe and Canada (RECODE) focused on linguistic diversity in the context of nation-states, the themes discussed in this volume mainly relate to the interplay of multilingualism, on the one hand, and the dynamics of transnationalism, globalisation and Europeanisation, on the other. Although there is an abundance of literature on multilingualism and diversity in the modern world, relatively little has been done towards elaborating an integrative view that identifies the key social and political dimensions at hand, and proposes a systematic approach to policy development on this basis. The purpose of this book is precisely to move in this direction.