Allan Rosas is one of the leading European Union jurists of his generation. His impact on the legal landscape of the EU has been immense. This collection brings together colleagues from the worlds of the judiciary, academia and practice to grapple with one of the key questions underpinning his contribution: is the trajectory of EU law one of ever-changing union? With essays exploring a range of topics from national identity and European construction to Brexit, this collection is a fitting tribute to an unrivalled EU law career.