Written in a clear style, the book's structured chapters provide a comprehensive analysis of the various foundations of obligation in international law: natural law, positivism and sociologism. Through this study, Robert Kolb illustrates how international law has been conceived and shaped over time in relation to its evolving historical and legal-political environment. Split into seven substantive parts, this text is one of the most detailed expositions of the doctrines of international law in the English language to date.

Astute and engaging, Robert Kolb's take on Truyol y Serra's Doctrines sur le fondement du Droit des gens will appeal to students and scholars of international law, as well as to practitioners interested in gaining a further grounding with regards to the basis of obligation in international law.