Modern Irish history was determined by the rise, expansion, and decline of the British Empire. British imperial history, from the age of Atlantic expansion to the age of decolonization, was moulded in part by Irish experience. But the nature of Ireland's position in the Empire has always been a matter of contentious dispute. Was Ireland a sister kingdom and equal partner in a larger British state? Or was it, because of its proximity and strategic importance, the Empire's most subjugated colony? Contemporaries disagreed strongly on these questions, and historians continue to do so. Questions of this sort can only be answered historically: Ireland's relationship with Britain and the Empire developed and changed over time, as did the Empire itself. This book offers the first comprehensive history of the subject from the early modern era through to the contemporary period. The contributors seek to specify the nature of Ireland's entanglement with empire over time: from the conquest and colonization of the sixteenth and seventeenth centuries, through the consolidation of Ascendancy rule in the eighteenth, the Act of Union in the period 1801-1921, the emergence of an Irish Free State and Republic, and eventual withdrawal from the British Commonwealth in 1948. They also consider the participation of Irish people in the Empire overseas, as soldiers, administrators, merchants, migrants, and missionaries; the influence of Irish social, administrative, and constitutional precedents in other colonies; and the impact of Irish nationalism and independence on the Empire at large. The result is a new interpretation of Irish history in its wider imperial context which is also filled with insights on the origins, expansion, and decline of the British Empire.