This week we will be hosting a discussion of Jean d’Aspremont’s recent book Formalism and the Sources of International Law: A Theory of the Ascertainment of Legal Rules, published by OUP in 2011. Jean is a prolific scholar and currently Associate Professor of International Law at the University of Amsterdam. He will be taking up a chair of public international law at the University of Manchester in January 2013, and has also blogged with us in the past. We will start off by an introductory post by Jean himself, and then proceed with comments by Philip Allott (Cambridge) and Carlos Esposito (UA de Madrid), concluding with the author’s response. The book being discussed was previously briefly noted in the EJIL by Monica Garcia-Salmones.