The essays in this collection explore the various ways in which a number of key European and International legal institutions attempt to define the boundaries of jurisdictional competence. The principle questions which are addressed are: (a) Does the relevant institution have a jurisdictional competence adequate to the challenges that it faces? (b) What are the parameters that bear upon the exercise of a particular jurisdictional competence? (c) What are the effects, positive or negative, of extending, restraining or creating a particular jurisdictional competence on those subject to its jurisdiction, other actors and the rule of law itself? Examples of the institutions covered in this book are the Security Council, the European Court of Justice, NATO, the International Court of Justice and the State.