This chapter explores the idea of a ‘tradition’ of comparative administrative law (CAL) in the trans-Atlantic Anglosphere. It first deals with a period from the early eighteenth to the late nineteenth century. At this time, Western comparative public law was predominantly an Anglo-European affair. The chapter next focuses on a period between about 1880 and 1940, a time of heavy intellectual traffic between England and the US, in which the birth of an identifiably Anglo-American tradition in comparative administrative law may be witnessed. Finally, the chapter is concerned with the impact on the Anglo-American tradition of the US Administrative Procedure Act (APA). The APA marked the maturation of American administrative law as a legal category concerned above all with judicial control of administrative power.