This work investigates the evolution and application of international legal principles through the lens of the International Court of Justice's jurisprudence over a fifty-year period. The author, H. W. A. Thirlway, leverages his extensive experience as a former Principal Legal Secretary to the Court to synthesize decades of legal analysis. By compiling and updating his contributions to the 'British Yearbook of International Law,' Thirlway provides a structured framework for understanding the Court's procedural and substantive developments since 1950.

Legal scholars and practitioners frequently cite this work as a foundational reference for understanding the internal mechanics and judicial reasoning of the International Court of Justice. Experts highlight the text's academic density and its utility as a primary resource for those studying the development of international legal doctrine.