This book provides a comprehensive and updated legal analysis of the equality principle in EU law. To this end, it argues for a broad definition of the principle, which includes not only its inter-individual dimension, but also the equality of the Member States before the EU Treaties. The book presents a collection of high-quality academic and expert contributions, which, in light of the most recent developments in implementing the post-Lisbon legal framework, reflect the current interpretation of the equality principle, examining its performance in practice with a view to suggesting possible solutions in order to overcome recurring problems. To this end the volume is divided into