The concept of deference is important in national legal systems, and this book is of considerable value in exploring the nature of the concept, and its application, in 17 different legal systems. This is more especially so, given the heterogeneity of the legal regimes covered in the book. The coverage includes common law and civilian legal systems, and the book is geographically diverse, embracing not only legal systems in Europe and the USA but also some from Latin America and Asia. This all adds to the richness of the collection, and its intellectual value, which is further augmented by an insightful introduction by the editor, Guobin Zhu. It is readily apparent from a number of the chapters in the book that it is necessary to disaggregate the concept of deference from the word itself. Concept and the language must be distinguished. The rationale for this varies as between legal systems. It may be that a particular legal system does not accept any deference whatsoever in dealings between courts and administration. This is possible in theory, but unlikely in reality. The more likely scenario is that the national legal order does acknowledge the substantive underpinnings of deference, to some degree at least, but there is judicial unease with use of the word “deference” itself. This is the reason for the point made at the outset of this paragraph, as to the importance of distinguishing between the concept of deference, in the sense of what it tells us about the relationship between courts and administration in judicial review, from use of the word.