During the sixteenth century, officials and interested parties in Ireland composed hundreds of papers on crown policy and sent them to the metropolitan government in England. The information contained in these 'reform' treatises substantially shaped how senior ministers in England viewed an Ireland which very few of them had visited personally. Moreover, these documents informed much of these ministers' outlooks on the Irish of Ireland and the allegedly backward political and social system operating there. These treatises argued for the adoption of specific policies to confront various problems perceived in Ireland. Some of these were highly coercive in arguing for 'reform' through an aggressive programme of regional conquest and colonization, while others had a more sanguine view of Ireland, proposing that 'reform' could be achieved through educational and social change, or the expansion of the court system. Whatever the approach, a great many of these policies were implemented in Ireland in due course. The decision to implement these policies played a major role in shaping the history of early modern Ireland and indeed the wider British state. As such, these treatises are central to how the Tudors governed Ireland. This book offers the first extended treatment of the approximately six-hundred extant 'reform' treatises. In doing so, it examines not just the content of this large body of papers, but how officials and other parties on the periphery of the Irish government debated policy in sixteenth-century Ireland and what impact their writings had.