Do different legal systems matter when it comes to General Principles? Do religious or Asian legal systems provide a different way of thinking about General Principles of international law? Do chthonic legal systems used by indigenous societies provide a better way of identifying General Principles? These are some of the questions that this provocative book helps to illuminate. The book further argues that General Principles have a global dimension. In order to account for some of the shortcomings in the present formation of General Principles, a new model and fresh perspectives are required to understand the historical evolution of General Principles. The prognosis by Saunders is that different legal systems need to be considered in order to fully diagnose General Principles, and that the full utilisation of those legal systems is warranted. This is a book with a thoughtful and lively narrative; Saunders’ account is readable and offers a new way of understanding and appreciating General Principles.

Readers are first introduced to a tetrahedral framework as a model for General Principles, which is a framework that deals with the function, type, methodology, and jurisprudential legitimacy of General Principles. Based on this framework, sometimes referred to as an “artificial exercise” (p. 20), Saunders delves into how international courts and tribunals, such as the Permanent Court of International Justice (PCIJ), the International Court of Justice (ICJ), the International Tribunal for the Law of the Sea (ITLOS), international criminal tribunals and regional human rights courts, handle General Principles. Saunders’ intervention in the ongoing debate on General Principles is rich, succinct, and traverses new terrains, including the various push and pulls of General Principles – are they rules, principles, or customs? Using the tetrahedral framework to develop her arguments, the duality of General Principles becomes clear (p. 137). Saunders forcefully argues that General Principles are “not simply European norms, or Western norms” (p. 274); that period of development, for Saunders, was only a certain point in time, which is necessary to understand, but the world has since moved on.

The first six chapters deal with the treatment of the historical evolution of General Principles by the international judiciary, while the seventh and eighth chapters offer a contextual discussion. This approach is familiar, but with a twist – the application of the tetrahedral framework. Throughout the discussions in the book, the ever-present tetrahedral framework of analysis reminds us of how essential the function, methodology, type, and “jurisprudential legitimacy” of General Principles are. For example, in the fourth and seventh chapters, judges at the PCIJ and the ICJ have rarely discussed the jurisprudential legitimacy criteria (or the norm content). Yet, it is a criterion that touches and shapes “all other” (p. 5) aspects of the tetrahedral framework. The book gives an account of a controversial area in international legal scholarship in order to understand the source of origins of General Principles and their contemporary relevance. Part of that relevance has to do with the global world in which we live, and therefore General Principles have a global function that requires taking into account other legal systems.

While Saunders recognizes that it was impossible to fully develop all her arguments in the book, this should not detract from the bigger picture of how General Principles and their dualities (principle/rule distinction, p. 270), sit within the fragmented approach of situating them at the doctrinal level and in the international judiciary. On a personal level, I suspect that since Saunders had developed some of her ideas in an earlier PhD project (most noticeably the tetrahedral model), it meant others have built upon her ideas and published their works prior to her excellent study. Nevertheless, since some of those works had “unsustainable” (p. 208) methods and applications, Saunders in her contribution manages to separate the “wheat from the chaff”.