International law concerns itself so largely with a state of war that the present world-conflict has necessarily had an important bearing upon many of its usages and principles and the opinion has been freely expressed, by some whose views are entitled to respect, that the events of this war have placed the science itself in jeopardy. Without attempting to express an opinion on that point, it is clear that when the war is over, one of the first tasks to be undertaken must be the readjustment of the dislocated parts of the system to the new conditions which have arisen. In doing this we shall probably be led to trace the development of the principles of international law from their earliest formulation up to the present day; but quite outside of this practical object, the accomplishment of which must be left to the future, it may not be without interest at the present time, from the purely historical point of view, to recur to some of the circumstances in which the science came into existence, by calling attention to a much neglected book which shows us in the making some of the important principles of international law which are at issue today, a book written by a man who introduced the modern method of studying that subject. The writer to whom reference is made is Alberico Gentili, and the work in question is his Advocatio Hispanica or the Pleas of a Spanish Advocate.