This book critically investigates the origins and consequences of the Janus-faced character of attitudes and policies towards migrants that seek to penetrate "Fortress Europe". Beginning with an examination of its founding ambitions, it locates the roots of an ingrained ambivalence in the legacies of the post-war period and the unresolved tension between the economicism of the European approach to labour migration and the philosophy of rights and solidarity embedded in the EU project. It highlights how the formalization of citizenship rights has produced both formal pathways towards inclusion for migrants and, in their selective eligibility criteria, exclusive systems of civic stratification. The author links this oscillation between positions of closure and openness to the paradoxical trade-offs in migration policies, in particular labour market integration, demonstrated through unequal labour market outcomes, lower social mobility and educational attainments. The issues faced by migrants' offspring in Europe are examined as paradigmatic of the struggle to balance competing calls for both pluralism and uniformity: to create a diverse society that can also project a homogenous collective identity. This balanced overview will provide an invaluable resource for students of migration studies, European politics, public policy, international relations and the sociology of racism.