Agreat export of Ireland in the 19th century was its people. From the 1830s to the 1950s, about eight million individuals permanently left Ireland, most crossing the wide Atlantic. This was one of the great migrations in history and has produced a mass of memoirs, analysis and reflections. Sean Connolly, an expert in the field, offers here an accessible and impressively lucid overview. His story starts just as the legendary attachment of the Catholic Irish peasant to their land of birth was beginning to wane as conditions at home degraded and opportunities abroad beckoned.

This was a migration of the masses. In the earliest years, passage to America was surprisingly cheap, accessible to all but the poorest peasantry. Ships to Britain brought bulky timber and cotton bales and carried away a much lighter cargo of textile goods. Irish emigrants in steerage were able to travel cheaply because they were, in effect, human ballast for the return journey.

In general, the transatlantic voyage was fairly safe, but when the years of the great hunger, 1845 to 1851, swelled the river of emigration to a flood, there was an awful climax of suffering on the ‘coffin ships’. In 1847, about 10 per cent of passengers died. One apparent novelty was the casual violence meted out by crew to bewildered and demoralised passengers. The receiving station at Grosse Ile in Canada became legendary for its horrifying levels of sickness and death. The misery of the refugees was indescribable, but Connolly succeeds in confronting us with its frightful horror.

The British government saw the famine as a providential opportunity to remake Ireland’s social structure. It bent policy towards forcing the clearance of peasants in favour of cattle and sheep. The effect was drastic. Pre-famine conventions of early marriage and subdivision of farms disappeared. It became normal to