The topic of sovereignty is contentious, and one of enduring interest. In a world of ever increasing economic globalisation, the rise of supranational regulation and the interconnected age of information and communication technology, among many other developments, have challenged the once exclusively held Westphalian model of sovereignty. The distinction between the internal aspect of sovereignty as expressed in terms of ultimate authority in a constitution, and the external aspect involving the relationship between sovereign states has been blurred. This has given rise to contemporary debates that explore the theoretical and practical implications of current challenges to established doctrines. Evidently no book could encompass the entirety of the contemporary debates on sovereignty. This is a book of essays focusing on sovereignty by a team of leading writers contributing domestic, European and international perspectives. The essays have been written at a time of very great testing of the institutional frameworks at every level: domestic, European, international or global. The book illuminates the enduring strength of sovereignty as a foundational concept and the continuing widespread appeal of sovereignty as an idea.