The term “lobbying” became established and was later applied to similar practices taking place within English local government organizations in the late 19th century, whereby petitioners would consult their representatives in a similar fashion. The development of European Union policymaking procedures and powers has shaped those who seek to influence it and vice versa. The European Union’s increasing influence upon national, sub-national, but also third country legislatures and regulatory frameworks has been characterized by Andersen and Eliassen and Beyers as Europeanization. The literature providing practical guidance on lobbying and public affairs in the European Union is small and pays little attention to the significant changes and professionalization recently experienced by European public affairs practitioners. The chapter provides some brief insights into the development of public affairs in the European Union context and sets the scene. It also presents an overview of the key concepts discussed in this book.