As an academic discipline in the United Kingdom, European Community law is a relative newcomer. I belong to the last generation that learnt its Community law on the hoof, through teaching it to others or practising it. I was, though, very fortunate in serving two apprenticeships, one, in the theory of the subject, under the late Professor J. D. B. Mitchell as a Lecturer in the Centre of European Governmental Studies at the University of Edinburgh and the other, in its practical application, as Legal Secretary to Sir Jean-Pierre Warner (as he became after his appointment to the Chancery bench of the High Court) when he was Advocate General at the Court of Justice of the European Communites. John Mitchell was an enthusiastic admirer of the Court of Justice and deeply learned in its ways; and one topic among many that interested him was the role of the Advocate General, a role it fell to J. P. Warner to show that a lawyer from this side of the Channel could fill with distinction. It was with my debt to those two masters very much in mind that the subject of this lecture was chosen.