Both the Appointed Day and the post-war arrival of colonial and Commonwealth immigrants heralded transformative change. Together, they reshaped daily life in Britain and notions of 'Britishness' alike. Yet the reciprocal impacts of post-war immigration and medicine in post-war Britain have yet to be explored. Contagious Communities casts new light on a period which is beginning to attract significant historical interest. Roberta Bivins draws attention to the importance - but also the limitations - of medical knowledge, approaches, and professionals in mediating post-war British responses to race, ethnicity, and the emergence of new and distinctive ethnic communities. By presenting a wealth of newly available or previously ignored archival evidence, she interrogates and re-balances the political history of Britain's response to New Commonwealth immigration. Contagious Communities uses a set of linked case-studies to map the persistence of 'race' in British culture and medicine alike; the limits of belonging in a multi-ethnic welfare state; and the emergence of new and resolutely 'unimagined' communities of patients, researchers, clinicians, policy-makers, and citizens within the medical state and its global contact zones.