=Observation.= The observation of the counter-battery fire, long-range fire on communication routes, and destructive fire on the interior of the position, falls upon the artillery’s ground observers and the aviation service. But the duty of observing the results of destructive fire on the enemy’s first line is carried out with the help of the infantry observers. Each regiment must observe the front upon which it is to make the attack. Special attention is paid to the destruction of barbed wire entanglements and machine gun emplacements. The interested infantry does not content itself with a passive observation, but must send out at night, or even in daylight, offensive reconnaissance parties. Their mission is to actually go into the enemy’s first line, to ascertain its condition, and to investigate the breaches in the hostile entanglements. The tactics of such a reconnaissance are the same as for a raid. The information gathered is sent to the division headquarters in the daily report of the intelligence officer or in special information reports. =Control.= It is both the privilege and the duty of the infantry commanders to state in their daily reports their opinion on the artillery preparation. If they do not express their exact opinion on the progress of the bombardment, they are liable to pay for their carelessness at the time of the assault. =Destruction of the Enemy’s Position.= The experiences of three years of trench warfare have given bitter proof that an attack against an insufficiently destroyed position will not only fail but will result in great losses. It is sheer folly to attempt an assault against undestroyed entanglements, or against a line in which the machine gun posts have not been demolished. One does not oppose materiel with men. In trench warfare, the conquest of the ground is made by the artillery; the infantry follow up this conquest to occupy and to hold the ground. The essential condition for the success of an attack depends upon the proper destruction of the elements of a position by the artillery. =Plan of Battle.= The plan of battle depends upon, first, the strength of the enemy, obstacles to the attacking troops, lines of defense, nests of resistances, barbed wire, etc.; and secondly, the mission of the attacking unit and the means at its disposal.