Huig de Groot, whom we know and venerate under the Latinized name of Hugo Grotius, is not a man with one book to his credit; but lawyers of all parts of the world are celebrating the three hundredth anniversary of one work of his, De Jure Belli ac Pacis Libri Tres. It appeared, it would seem, sometime in the month of March, 1625. For many years it was looked upon as a tour deforce, as an extraordinary achievement for a politician in exile and a humanist to his finger-tips to have turned off within the space of a few months a treatise on a dry and admittedly technical subject, whose principles were ill-defined and, where known, were treated with scant respect.