Apart from military force, the common law was the most powerful instrument of the English administration in the control of Ireland. Sir John Davies was its most articulate advocate and imagined that the common law would pervade almost all aspects of life as it did in England. For Catholics, the common law became of increasing importance in the seventeenth century, particularly in relation to land ownership and the practice of religion. But could a legal system which emanated from a polity founded on Protestantism accommodate a Catholic population? The Irish parliament enacted legislation which had profound and enduring consequences. The administration issued hundreds of proclamations which had pervasive effect. The land settlement, restraints on the practice of religion and periods of persecution ensured that Catholics had particularly intense encounters with the law. Yet references to the role of the law in studies of the Restoration are scant, and few acknowledge its centrality. Since Catholics constituted the largest proportion of the population, there is a major lacuna in the historiography. The object of the book is to explore and illustrate some aspects of how Irish Catholics engaged with and experienced the common law. This is a vast topic and the book endeavours to take up the challenge of an interdisciplinary approach through a series of case studies. It does not aspire to be comprehensive.