The field of comparative administrative law has developed less extensively than comparative constitutional law. While it is experiencing a recent growth in interest, there remain gaps in the depth and extent of study, especially across common law systems. This Chapter evaluates common law studies to date, with a view to highlighting the relatively small catchment of common law systems in those studies, with the focus typically being on key Anglo-American systems. As common law systems increasingly diversify, there is much to be gained in exploring the diversity of common law approaches to administrative law. The comparative conversation will be assisted with input from a broader range of common law jurisdictions, especially those outside the traditional focus of comparative administrative law, in particular systems from Asia. This Chapter proposes that one avenue to do this is to compare the origins and adaptations of English law principles of judicial review across common law systems that traditionally imported, or were modelled on, English law. Such a conversation will help develop a much more robust understanding of different approaches to judicial review that is not skewed towards an English or ‘Westminster- system’-based understandings. This is the ambition of this Volume. This is especially for the benefit of ‘newer’ common law jurisdictions that are undergoing a more nascent development of administrative law and looking for inspiration on modes of development. This more refined understanding of ‘common law’ approaches to judicial review will also provide a better launch pad for studies of common law versus civil law systems, which have until now tended to be driven by a ‘unitary’ or narrow understanding of ‘common law’ systems as a, more or less, unified group of systems with certain shared characteristics.