This chapter probes the borders of the public supervisory jurisdiction by looking at a parallel private law supervisory jurisdiction under which the courts judicially review decisions by "domestic tribunals". This comparative exercise gives pause for reflection on the deeper conceptual and normative foundations of judicial review, especially for questions of amenability to review. In the modern administrative state, many apparently "public" functions are performed by private, profit-oriented or charitable bodies and the review of these bodies has been an important testing ground in which theories of judicial review have been formulated and defended. Stopping short of suggesting a grand, unified theory of all the supervisory jurisdictions, I argue that an appreciation of the deep, structural parallels helps us to understand the common law roots of judicial review and that office could provide some intellectual resources to advance the province of administrative law judicial review in a principled fashion.