The third edition of this leading text provides a detailed account of the purposes of judicial review; the nature of the public-private divide in Northern Ireland law; the judicial review procedure; the grounds for review; and remedies. As with the previous editions, the focus is on case law that is unique to Northern Ireland, and the book identifies some important differences between principle and practice in Northern Ireland and England and Wales. These now include differences resulting from the Ireland-Northern Ireland Protocol (as amended by the Windsor Framework), and this edition explains how and when EU law continues to apply in Northern Ireland. It also considers the leading Human Rights Act decisions of the Northern Ireland courts and the House of Lords and UK Supreme Court. The new edition refers to leading case law from the courts in England and Wales and Scotland; the Court of Justice of the European Union; and the European Court of Human Rights. There is a particular focus on recent rulings of the High Court and Court of Appeal in Northern Ireland and of rulings of the Supreme Court in cases heard on appeal from Northern Ireland. It considers the main points of the Judicial Review Practice Direction 03-2018 and surveys the European Union (Withdrawal) Act 2018 and its implications for Northern Ireland (including the incorporation of the Ireland-Northern Ireland Protocol, as amended by the Windsor Framework). The book will be of use to practitioners in Northern Ireland and elsewhere in the UK, and also to those involved in the study of judicial reasoning in different jurisdictions (both within the UK and elsewhere).