This book investigates uncertainty as a governing practice from the unique vantage point of 'citizenisation' – twenty-first-century integration and naturalisation measures that make and unmake citizens and migrants, while indefinitely holding many applicants for citizenship in the waiting room of citizenship.  Uncertain Citizenship investigates uncertainty as a governing practice from the vantage point of 'citizenisation' - 21st-century integration and naturalisation measures that make and unmake citizens and migrants, while indefinitely holding many applicants for citizenship in the waiting room of citizenship. Fortier's distinctive theory of citizenisation foregrounds how the full achievement of citizenship is always deferred. If migrants and citizens are continuously citizenised, so too are they migratised. Drawing on multi-sited fieldwork with migrants and with intermediaries of the state tasked with implementing citizenisation measures, Fortier scrutinises life in the waiting room and shows how citizenship takes place, takes time and takes hold in ways that conform, exceed, and confound frames of reference laid out in both citizenisation policies and taken-for-granted understandings of 'citizen', 'migrant', and their relationships to citizenship.