In the late 1950s, jurists engaged in intense debates about the terminology of European law. Terms such as supranationality, confederation of states, or federal state were regarded as shaped by the nation-state and as polarizing. Linguistic innovations, distinct linguistic rules for European law, and a language of imagery and metaphor were needed. A linguistic transformation took place-a transitional period (a Sattelzeit) that continues to shape how we communicate about European law today. The term Sattelzeit is coined in reference to the conceptual historian Reinhart Koselleck and denotes a particularly profound shift in language. With this European Sattelzeit, indeterminate associative terms and modes of expression became established in European law that raise difficult questions-for example, whether European law and national law constitute one, two, or several legal orders; whether European law has its own source of law; whether it was created through an overarching act; or whether it is a "community of law." Such formulations have not only made the specialist language of European law more confusing, but presumably also more political. The approach of the present study is both historical-critical and analytical. Who used which legal expressions, for what purpose? And what are good linguistic rules for our specialist language of European law? Thorben Klünder systematizes the vocabulary of European law, traces its historical development, and offers a critique of European legal language, metaphor, and theory.