This book presents a positive account of state aid law at the EU, UK, and global levels, and provides the keys to understanding how it is adjusting to emerging realities.Industrial policy, decarbonisation, de-risking of supply chains: the regulation of subsidies is at the forefront of the transformations that the world economy is undergoing. The book provides an overview of the foundations of EU State aid law, one of the most dynamic areas of EU law. An up-to-date and accessible framework explains the core conditions underpinning the notion of State aid including advantage and selectivity.The book also covers how the EU model has changed over the past decade. It helps navigate the complex case law on the application of EU State aid law to tax rulings concluded with large multinationals (such as the Apple saga) as well as the perma-crisis of the regime since the COVID pandemic.The ways in which the EU model extends its reach beyond its borders convergence and unilateral expansion are also addressed. The UK Subsidy Control Act 2022 and the EU Foreign Subsidies Regulation are discussed and put in context.Conceived as a 'modular' book, it can be used both as a tool to navigate the fundamentals of the discipline and as a map to reflect upon its uncertain future.