International responsibility law today is in great need of theorizing or, at least, that is the present volume’s argument. This introduction sets the stage for that argument. It unfolds in four steps: first, it clarifies the reasons that led to putting this collection of essays together and explains what it hopes to achieve; second, it introduces the main theoretical challenges addressed in the volume; third, it provides some information about how the book is organized; and, finally, it sketches out the content of its successive chapters and their articulation.

In De jure belli ac pacis, Grotius constructs international law with the vocabulary of private law. For this purpose, he uses distinctions from the Institutes of Justinian and the Digest, but redefines key concepts of Roman law, such as natural law or law of nations (jus gentium). In doing so, he uses a method that is typical for humanist jurisprudence. On the one hand, he describes history, on the other hand, he renews the traditional system of law and adapts the law to the needs of his own day and age.

What is the legacy of Grotius’ doctrinal efforts, and how did they impact on current structures of international law? Was he providing a natural law foundation for the global order, or rather an instrument of power for sovereigns to assert their political and commercial dominion over the world?