In the year 1846, Captain William C. De Hart, of the Second Artillery, published his excellent work, entitled, "Observations on Military Law, and the Constitution and Practice of Courts-Martial." In his Preface he says,--"Since the legal establishment of the army and navy of the United States, there has been no work produced, written for the express purpose,... and intended as a guide for the administration of military justice." And, in a note, he adds, "The small treatise on courts-martial by the late Major-General Macomb is no exception to the remark." He makes, if we remember rightly, no reference to Captain O'Brien's work, which appeared but a short time before his own. The work of Captain De Hart, so far in advance of what had yet appeared on this subject, written, too, by an expert, who had been long employed under the orders of the War Department as the acting judge-advocate of the army, (the office of judge-advocate not being created till a later day,) was regarded as the chief authority in the army. But it was never designed, nor can it be easily adapted, for instruction. It is a philosophical discussion of the subject, containing many historical citations and illustrations, which show the reader his authorities without fortifying his positions. For a text-book, therefore, it lacks arrangement, and is too discursive. Up to this time, the subject of military law was not studied at the Military Academy; but in the year 1856, when the course of studies in that institution was lengthened, so as to consume five years instead of four, this branch was added to the curriculum, and has since been retained,--its importance being made every day more manifest. Then a treatise was wanted, which, while it could be used as authority in our vast army, should be also suited as a text-book for the cadets, from which they could recite in the section-room, and which should be their _vade-mecum_ for future reference,--originally learned, and always consulted. This was Captain Benét's self-appointed task, and he has performed it admirably. He has examined all the authorities, French and English, and his book bears the evidences of this original investigation. For purposes of study, his system is clear, his arrangement logical, and his divisions numerous and just. All the directions as to _trials_ are very practically set forth, so that any sensible volunteer officer, appointed upon a court unexpectedly, could very soon, by the aid of these pages, make himself "master of the position." And as there is much concurrent, and sometimes apparently conflicting, jurisdiction of military and civic courts, this volume ought to be on every lawyer's table as the special expounder of military law, wherever it may approach the action of the civil code.