‘The history of migration is a history of alienation and its consequences’. That was the verdict of Oscar Handlin on the collective experience of 35 million immigrants in the United States in the century after 1820. Migration has always been a contentious phenomenon, the controversy generally focusing on whether it was beneficial or detrimental to the security and prosperity of donor and recipient countries and communities. The recurring, and much debated, dilemma for politicians and employers in places of supply was whether to promote or discourage an outflow that might—depending on circumstances—be hailed as an escape route for the destitute and disaffected, or demonized as a debilitating loss of brain, brawn and capital. Meanwhile, host societies were equally ambivalent about whether new arrivals represented a welcome injection of cheap labour or an offloading of the unemployable.