This is the first volume of proceedings arising from the bi-ennial conference of the European Society of International Law/Societe europeene de droit international (ESIL/SEDI). The book presents the highlights of the Paris Conference 2006, which, through plenary sessions, fora, and agorae, the Conference sought an answer to the question International Law: Do We Need It? The collection of papers are evenly divided between English and French language contributions. Future volumes in this series will further reflect other major ESIL/SEDI events.