During the fifteen years following the Second World War, ‘transnational’ (activities, enterprises, organisations, networks, movements, processes, law) had not yet become a household word – even in academic households. But the times were propitious for its coinage and rapid evolution as a commonly used descriptive term with ever-broadening references. With its distinctive form of stability among major States imposed by the Cold War, this period and the following decades witnessed dramatic recovery from the war's massive devastation. It gave birth to many intergovernmental organisations and multinational companies, as well as to new practices and rules for international finance, international trade and investment, peacekeeping and human rights. These years generated heightened international flows of goods and capital and new types of international intercourse. Traditional classifications of the many bodies of law and kinds of transactions germane to international life bowed to the new circumstances and to a fresh vocabulary. The term ‘transnational’ emerged as a winner.

Such was the period of Detlev Vagts' university education, military service and brief but instructive career as a practising lawyer involved with international corporate and financial transactions, all a prelude to his almost fifty years of professorial engagement with this new and volatile world. Much of Detlev's teaching and scholarship fell comfortably within the developing idea or category of the transnational. His work transcended the boundaries of any one of the component fields included in the concept of transnational law.