In the last two decades, the term ‘fair taxation’ has become ubiquitous in the European public debate. From a political economy perspective this increased popularity is not difficult to understand: the term is sufficiently vague to cover different taxing preferences, appropriately simple to be intuitively understood by voters, and suitably pro-social to convey a compelling story. From a normative perspective, however, it is precisely this vagueness and simplicity that renders the term problematic. From both a theoretical and a policy perspectives, what is meant by fair taxation? What is the impact of taxation on inequalities, broadly construed, and to what extent should the tax system be used to redress them? To answer these questions, the European Association of Tax Law Professors (EATLP) embarked on a massive global research project on ‘Taxation and Inequalities’ in 2022. The overall aim of the project is to fill the scholarship gap and inform policy, by presenting a novel analytical and conceptual framework of taxation and inequalities, informed not solely by tax law, but also by human rights, constitutional and administrative law, as well as public economics, political economy, moral philosophy, and moral and social psychology. This Editorial introduces the core issues at stake, as discussed at the EATLP Congress, held at Antwerp University, in June 2024.