This detailed study provides a thorough overview and critical discussion of conceptions and measures of the rule of law. It demonstrates that the choice of definitions and measures affects descriptive and explanatory findings in respect to the rule of law. Moreover, it argues that a constitutionalist legacy dating back to the Mediaeval times explains why European and European settler colonies have historically and habitually display a higher adherence to and reliance on nomocracy than other countries and why this trend has continued to this day. By integrating conceptual definitions, measures, patterns, and causes, this book presents a comprehensive and coherent framework for studying the rule of law, which students and scholars can use as a general entry point to the literature to the subject and why we see such significant variation in nomocracy adherence between different countries today.--