A discussion, in terms of the qualities of resolution and perception in military leaders, of the careers of General Joseph Jacques Cesaire Joffre, leader of the French Armies at the outset of World War I, and General Charles Lanrezac, selected by Joffre to conduct the difficult operations of the French left wing and later dismissed. Joffre's position is discussed in the context of Plan XVII, which he and his staff devised between 1911 and 1914 for the conduct of operations against the Germans. Joffre emerges as a hero because of his indomitable will, but his blindness and strategic inadequacy were largely responsible for the heavy price that France paid in the opening engagements of the war. Few remember that it was Lanrezac who deprived the Germans of their opportunity for a major strategic success through his skillful reading of the military situation during these opening engagements. 34 pp. Bibliog.