for a key-word to define the general idea of the offensive, that key-word would probably be "exploitation." It was not intended merely to break through the enemy's defences, to strike him a heavy blow; it was designed to exploit a preliminary success, to clear a great tract of country of hostile troops, to turn a flank; for, be it remembered, the advance to the Sensée marshes would have involved not merely a headlong retreat or wholesale capture for the German troops south of them, but an eventual retirement of several miles at least to the north. The Drocourt-Quéant Switch, the main Hindenburg Lines, would be gone. Cambrai was, for the Western Front, a small battle, but great events hung upon it. In the previous accounts of battles it has not been necessary, for the purpose of writing the History of the 36th Division, to do more than glance at the progress of the Divisions fighting upon its flanks. In this battle, on the contrary, if any adequate conception is to be reached from the account, the plan and the action of the IV. Corps, that is, of the two Divisions on the right of the 36th, and the 56th Division, which was under the orders of the IV. Corps for the greater part of the action, must be studied in some detail. The right boundary of the IV. Corps was the Trescault-Ribécourt Road; thence north of Noyelles. It was to attack with three Divisions, the 51st on the right, the 62nd in the centre, and the 36th on the left. The 51st and 62nd Divisions, the left of the latter on the Canal du Nord, were to advance north from the skirts of Havrincourt Wood. The normal northern objective of the first day was the Bapaume-Cambrai Road. If, however, there was little opposition, the 51st and 62nd Divisions were to press on and take the high ground crowned by Bourlon Wood and village, or take them over from the Cavalry if the latter had occupied them, while the 107th and 108th Brigades of the 36th Division moved parallel with them east of the Canal, formed a flank-guard facing west, and seized the passages of the Canal at Mœuvres and Inchy-en-Artois. In the event of serious opposition this later programme was to be that of the next day. The primary task of the 36th Division was to capture the German trenches west of the Canal du Nord and south of the Bapaume-Cambrai Road. For this it was to employ one Brigade, the 109th, one of its Field Artillery Brigades, the 173rd, together with the 280th Brigade and the 93rd Army Brigade R.F.A. Its other Artillery Brigade, the 153rd, was at the disposal of the 62nd Division, to take part in its preliminary barrage. The plans were entrusted to General Ricardo, who worked them out with his Artillery Group Commander, Lieut.-Colonel H. C. Simpson, D.S.O., and had thus an almost unique opportunity for a Brigadier on the Western Front of fighting his own battle in his own fashion. Communication across the Canal was to be established by the erection of a bridge on the Demicourt-Flesquières Road, to take wagons and