"Michael Scharf's Customary International Law in Times of Fundamental Change: Recognizing Grotian Moments is a masterful look at when and how radical developments accelerate the emergence of customary international law (described as "Grotian Moments"). Scharf's careful development of the concept of Grotian Moments is to be applauded. His book closely analyses six scenarios from recent history in order to better identify both when such moments occur and when it seems like they might occur but nevertheless do not materialize. Why have some controversial legal pronouncements, such as joint criminal enterprise liability and the Tadic Appeals Chamber's holding on the scope of ICTY's provision regarding violations of the laws or customs of war, rapidly gained acceptance as customary international law? Why have other controversial legal pronouncements, such as the responsibility to protect doctrine and the recent expansion of the concept of anticipatory self-defense, not gained such rapid acceptance? Scharf newest work gives careful scrutiny to these legal issues and many others, and what results is a piece of scholarship from which international courts from this point forward can use to understand when customary international law develops and, just as importantly, why." Judge Christine Van den Wyngaert, International Criminal Court newest work gives careful scrutiny to these legal issues and many others, and what results is a piece of scholarship from which international courts from this point forward can use to understand when customary international law develops and, just as importantly, why." Judge Christine Van den Wyngaert, International Criminal Court newest work gives careful scrutiny to these legal issues and many others, and what results is a piece of scholarship from which international courts from this point forward can use to understand when customary international law develops and, just as importantly, why." Judge Christine Van den Wyngaert, International Criminal Court newest work gives careful scrutiny to these legal issues and many others, and what results is a piece of scholarship from which international courts from this point forward can use to understand when customary international law develops and, just as importantly, why." Judge Christine Van den Wyngaert, International Criminal Court.