This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book introduces the changes in the International System and their consequences in terms of increasing mobility and security issues, along with its interrelation with the 9/11 attack and its undermining of peaceful international relations across the globe. It emphasizes how the above mentioned facts have subsequently become sources of new perceived threats and the reasons for which new exclusionary patterns have arisen, exacerbating the perceived clash of civilizations and the root causes of different fashions of extremisms: neo-fascist and terrorist groups. The book considers more optimistic views, by showing how alternative ways to deal with the instability already exist and are practicable to a wider extent, through a partnership of different stakeholders. It presents a unique cross-cutting angle, though building on existing debates, including the securitization of migration, the global politics of migration and the integration of migrants in Europe and beyond.