From the ancient beginnings of Western legal tradition, law has been conceived as traversed by a fundamental tension between power (will) and reason. This volume examines the tension between these two poles, ‘ratio and voluntas’ in modern law. Part I focuses on three instructive phases in the history of the law’s ratio. Part II examines the way legal scholarship, especially doctrinal research (legal dogmatics), can and should contribute to the law’s coherence. Part III explores the role of constitutional law in managing the tension between law’s voluntas and ratio. The final chapter discusses the implications the growth of transnational law may have on the relationship between ratio and voluntas. The study builds on the views of the distinctive features of the ideal-typical mature modern legal system as presented in the author’s previous work, Critical Legal Positivism (Ashgate 2002).