Since Brexit in 2016 there has been an undeniable groundswell of public interest in the possibility of holding referendums to create a new and united Ireland as provided for by the 1998 Good Friday peace agreement. The resulting debate on Irish unity has highlighted the legal and policy differences that have resulted from 100 years of separate development in the two polities, the economic barriers which the post-Brexit border has regenerated, and the increasingly divergent political values between Ireland and the UK. These factors have rejuvenated interest in the question of Irish unity and have increased awareness of the detailed planning that would be necessary to create a new state. This emerging discourse has also demonstrated that there is a high level of ignorance and misinformation about the comparative economic and public policy frameworks of the two jurisdictions. Active civil society groups and the general public in the North are uninformed about conditions in the South, and civil society and the general public in the South are equally uninformed about the North. The genesis of this book lies in a number of research projects which explored these policy differences and civil society’s level of awareness of them. Its purpose is not to argue for or against a united Ireland, but rather to bring together the existing evidence on the key issues which will be at the heart of the debate. It also deals with how a debate on the future of the island of Ireland will be managed and the range of constitutional and policy options that would be available to the new state.