The Internal Market Ideal honours the pathbreaking work of Professor Stephen Weatherill, Jacques Delors Professor of European Law at the University of Oxford (1998-2021). For more than three decades, Professor Weatherill has been the dominant figure in internal market debates, shaping the European Union's Internal Market both at Oxford and internationally. Looming large in fields as disparate as consumer protection and sports law, his voice has guided how relevant laws and regulations are understood and how their varying virtues and pitfalls are perceived. A reference to his seminal work The Internal Market as a Legal Concept (OUP, 2016), the present volume is not simply a celebration of Weatherill's scholarship, but also an examination of the legal issues surrounding the semi-integrated market of the European Union. Across nineteen essays, the collection presents a vision of the European Union not yet achieved; that is, a Union which benefits from economic growth and pursues non-economic objectives, whilst carefully balancing respect for Member States' autonomy and the European Union's self-sufficiency. The Internal Market Ideal is an invaluable resource for students, researchers, practitioners, and policy makers in the field of European Law.