This monumental contemporary treatise was undertaken by the author, Professor J.W. Garner, at the request of Dr. L. Oppenheim, then Whewell Professor of International Law at the University of Cambridge. It was Oppenheim's desire that Garner should "review the conduct of the belligerents in respect to their interpretation and application of the rules of international law, compare it with the opinions of the authorities and the practice in former wars and wherever infractions appeared, to endeavor to determine the responsibility and to place it where it properly belonged".

Some contemporary book reviews

"Garner reviews the interpretation and application of international law by belligerent Nations during the First World War, comparing it with the opinions of authorities and practice in former wars. Wherever Garner detects infractions, he endeavors to show who was responsible and what should have been done. Professor Garner is to be congratulated upon having sifted through a great mass of detail and given a sequent, detailed, and interesting account of the various legal controversies arising during the war". Frederic R. Coudert, Yale Law Journal, 31 (1921-1922), p 228.

"The author has performed this task as thoroughly and comprehensively as Dr. Oppenheim himself might have done it, had he lived to undertake and execute such a work. With reservations as to style in favor of Professor Garner, the reviewer is incapable of higher praise than this. [...] Of course one important test of the value of such a work as this is its spirit of impartiality. Professor Garner might perhaps be accused of leaning too far backwards by some critics of German atrocities and other manifold violations of international law. From the fact that the verdict is almost uniformly unfavorable to Germany, other critics might possibly draw the interference that he has shown a nationalistic bias. [...] From the viewpoint of the international jurist, the greatest omission may well appear to be a fuller discussion of the imperfections of the rules of land warfare as revealed by military practice, suggested solutions of the many unsettled questions of maritime and aerial law, and the possibilities of future developments. Professor Garner has, however, supplied us with what is most needed at this time - a thorough, accurate, well-digested, and comprehensive knowledge of well-documented materials illustrative of practice during the World War. He has also pronounced many valuable expert judgments". Amos S. Hershey, The Journal of International Relations, 12 (1921), No. 1, pp. 110-112.